4-(p-quinonyl)-2-hydroxybutanamide derivatives for treatment of mitochondrial diseases

ABSTRACT

Methods of treating or suppressing mitochondrial diseases, such as Friedreich&#39;s ataxia (FRDA), Leber&#39;s Hereditary Optic Neuropathy (LHON), mitochondrial myopathy, encephalopathy, lactacidosis, and stroke (MELAS), Kearns-Sayre Syndrome (KSS), are disclosed, as well as compounds useful in the methods of the invention, such as 4-(p-quinolyl)-2-hydroxybutanamide derivatives. Methods and compounds useful in treating other disorders such as amyotrophic lateral sclerosis (ALS), Huntington&#39;s disease, Parkinson&#39;s disease, and pervasive developmental disorders such as autism are also disclosed. Energy biomarkers useful in assessing the metabolic state of a subject and the efficacy of treatment are also disclosed. Methods of modulating, normalizing, or enhancing energy biomarkers, as well as compounds useful for such methods, are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. application Ser. No.16/228,657, filed Dec. 20, 2018, which is a continuation of U.S.application Ser. No. 15/374,916, filed Dec. 9, 2016, now U.S. Pat. No.10,167,251, which is a continuation U.S. application Ser. No.14/829,534, filed Aug. 18, 2015, now U.S. Pat. No. 9,546,132, which is adivisional of U.S. application Ser. No. 13/924,363, filed Jun. 21, 2013,now U.S. Pat. No. 9,169,196, which is a continuation U.S. applicationSer. No. 13/110,830, filed May 18, 2011, now U.S. Pat. No. 8,519,001,which is a divisional of U.S. application Ser. No. 12/264,838, filedNov. 4, 2008, now U.S. Pat. No. 7,968,746, which claims benefit of U.S.Provisional Patent Application No. 61/002,126, filed on Nov. 6, 2007 andof U.S. Provisional Patent Application No. 61/002,127, filed Nov. 6,2007. The entire contents of these those patent applications are herebyincorporated by reference herein in their entireties.

TECHNICAL FIELD

The application discloses compositions and methods useful for treatment,prevention, or suppression of diseases, developmental delays andsymptoms related to mitochondrial disorders, such as Friedreich'sAtaxia, Leber's Hereditary Optic Neuropathy, Kearns-Sayre Syndrome,mitochondrial myopathy, encephalopathy, lactacidosis, and stroke, andcerebral vascular accidents, and for modulating energy biomarkers in asubject. Compositions of the present invention are administered to asubject for the purpose of compensating for mitochondrial dysfunctionand for improving mitochondrial functions. Methods and compounds usefulin treating other disorders such as Amyotrophic Lateral Sclerosis (ALS),Huntington's and Parkinson's are also disclosed.

BACKGROUND

Mitochondria are organelles in eukaryotic cells, popularly referred toas the “powerhouse” of the cell. One of their primary functions isoxidative phosphorylation. The molecule adenosine triphosphate (ATP)functions as an energy “currency” or energy carrier in the cell, andeukaryotic cells derive the majority of their ATP from biochemicalprocesses carried out by mitochondria. These biochemical processesinclude the citric acid cycle (the tricarboxylic acid cycle, or Kreb'scycle), which generates reduced nicotinamide adenine dinucleotide(NADH+H⁺) from oxidized nicotinamide adenine dinucleotide (NAD⁺), andoxidative phosphorylation, during which NADH+H⁺ is oxidized back toNAD⁺. (The citric acid cycle also reduces flavin adenine dinucleotide,or FAD, to FADH₂; FADH₂ also participates in oxidative phosphorylation.)

The electrons released by oxidation of NADH+H⁺ are shuttled down aseries of protein complexes (Complex I, Complex II, Complex III, andComplex IV) known as the respiratory chain. These complexes are embeddedin the inner membrane of the mitochondrion. Complex IV, at the end ofthe chain, transfers the elections to oxygen, which is reduced to water.The energy released as these electrons traverse the complexes is used togenerate a proton gradient across the inner membrane of themitochondrion, which creates an electrochemical potential across theinner membrane. Another protein complex, Complex V (which is notdirectly associated with Complexes I, II, III and IV) uses the energystored by the electrochemical gradient to convert ADP into ATP.

The citric acid cycle and oxidative phosphorylation are preceded byglycolysis, in which a molecule of glucose is broken down into twomolecules of pyruvate, with net generation of two molecules of ATP permolecule of glucose. The pyruvate molecules then enter the mitochondria,where they are completely oxidized to CO₂ and H₂O via oxidativephosphorylation (the overall process is known as aerobic respiration).The complete oxidation of the two pyruvate molecules to carbon dioxideand water yields about at least 28-29 molecules of ATP, in addition tothe 2 molecules of ATP generated by transforming glucose into twopyruvate molecules. If oxygen is not available, the pyruvate moleculedoes not enter the mitochondria, but rather is converted to lactate, inthe process of anaerobic respiration.

The overall net yield per molecule of glucose is thus approximately atleast 30-31 ATP molecules. ATP is used to power, directly or indirectly,almost every other biochemical reaction in the cell. Thus, the extra(approximately) at least 28 or 29 molecules of ATP contributed byoxidative phosphorylation during aerobic respiration are critical to theproper functioning of the cell. Lack of oxygen prevents aerobicrespiration and will result in eventual death of almost all aerobicorganisms; a few organisms, such as yeast, are able to survive usingeither aerobic or anaerobic respiration.

When cells in an organism are temporarily deprived of oxygen, anaerobicrespiration is utilized until oxygen again becomes available or the celldies. The pyruvate generated during glycolysis is converted to lactateduring anaerobic respiration. The buildup of lactic acid is believed tobe responsible for muscle fatigue during intense periods of activity,when oxygen cannot be supplied to the muscle cells. When oxygen againbecomes available, the lactate is converted back into pyruvate for usein oxidative phosphorylation.

Mitochondrial dysfunction contributes to various disease states. Somemitochondrial diseases are due to mutations or deletions in themitochondrial genome. If a threshold proportion of mitochondria in thecell is defective, and if a threshold proportion of such cells within atissue have defective mitochondria, symptoms of tissue or organdysfunction can result. Practically any tissue can be affected, and alarge variety of symptoms may be present, depending on the extent towhich different tissues are involved.

One such disease is Friedreich's ataxia (FRDA or FA). Friedreich'sataxia is an autosomal recessive neurodegenerative andcardiodegenerative disorder caused by decreased levels of the proteinfrataxin. Frataxin is important for the assembly of iron-sulfur clustersin mitochondrial respiratory-chain complexes. Estimates of theprevalence of FRDA in the United States range from 1 in every22,000-29,000 people (seewww.nlm.nih.gov/medlineplus/ency/article/001411.htm) to 1 in 50,000people (see www.umc-cares.org/health_info/ADAM/Articles/001411.asp). Thedisease causes the progressive loss of voluntary motor coordination(ataxia) and cardiac complications. Symptoms typically begin inchildhood, and the disease progressively worsens as the patient growsolder; patients eventually become wheelchair-bound due to motordisabilities.

Another disease linked to mitochondrial dysfunction is Leber'sHereditary Optic Neuropathy (LHON). The disease is characterized byblindness which occurs on average between 27 and 34 years of age;blindness can develop in both eyes simultaneously, or sequentially (oneeye will develop blindness, followed by the other eye two months lateron average). Other symptoms may also occur, such as cardiacabnormalities and neurological complications.

Yet another devastating syndrome resulting from mitochondrial defects ismitochondrial myopathy, encephalopathy, lactacidosis, and stroke(MELAS). The disease can manifest itself in infants, children, or youngadults. Strokes, accompanied by vomiting and seizures, are one of themost serious symptoms; it is postulated that the metabolic impairment ofmitochondria in certain areas of the brain is responsible for cell deathand neurological lesions, rather than the impairment of blood flow asoccurs in ischemic stroke. Other severe complications, includingneurological symptoms, are often present, and elevated levels of lacticacid in the blood occur.

Another mitochondrial disease is Kearns-Sayre Syndrome (KSS). KSS ischaracterized by a triad of features including: (1) typical onset inpersons younger than age 20 years; (2) chronic, progressive, externalophthalmoplegia: and (3) pigmentary degeneration of the retina. Inaddition, KSS may include cardiac conduction defects, cerebellar ataxia,and raised cerebrospinal fluid (CSF) protein levels (e.g., >100 mg/dL).Additional features associated with KSS may include myopathy, dystonia,endocrine abnormalities (e.g., diabetes, growth retardation or shortstature, and hypoparathyroidism), bilateral sensorineural deafness,dementia, cataracts, and proximal renal tubular acidosis. Thus, KSS mayaffect many organ systems.

Co-Enzyme Q10 Deficiency is a respiratory chain disorder, with syndromessuch as myopathy with exercise intolerance and recurrent myoglobin inthe urine manifested by ataxia, seizures or mental retardation andleading to renal failure (Di Mauro et al., (2005) Neuromusc. Disord.,15:511-315), childhood-onset cerebellar ataxia and cerebellar atrophy(Masumeci et al., (2001) Neurology 56:849-855 and Lamperti et al.,(2003) 60:1206:1208); and infantile encephalomyopathy associated withnephrosis. Biochemical measurement of muscle homogenates of patientswith CoQ10 deficiency showed severely decreased activities ofrespiratory chain complexes I and II+III, while complex IV (COX) wasmoderately decreased (Gempel et al., (2007) Brain, 130(8):2037-2044).

Complex I Deficiency or NADH dehydrogenase NADH-CoQ reductase deficiencyis a respiratory chain disorder, with symptoms classified by three majorforms: (1) fatal infantile multisystem disorder, characterized bydevelopmental delay, muscle weakness, heart disease, congenital lacticacidosis, and respiratory failure; (2) myopathy beginning in childhoodor in adult life, manifesting as exercise intolerance or weakness; and(3) mitochondrial encephalomyopathy (including MELAS), which may beginin childhood or adult life and consists of variable combinations ofsymptoms and signs, including ophthalmoplegia, seizures, dementia,ataxia, pigmentary retinopathy, sensory neuropathy, and uncontrollablemovements.

Complex II Deficiency or Succinate dehydrogenase deficiency is arespiratory chain disorder with symptoms including encephalomyopathy andvarious manifestations, including failure to thrive, developmentaldelay, hyoptonia, lethargy, respiratory failure, ataxia, myoclonus andlactic acidosis.

Complex III Deficiency or Ubiquinone-cytochrome C oxidoreductasedeficiency is a respiratory chain disorder with symptoms categorized infour major forms: (1) fatal infantile encephalomyopathy, congenitallactic acidosis, hypotonia, dystrophic posturing, seizures, and coma;(2) encephalomyopathies of later onset (childhood to adult life):various combinations of weakness, short stature, ataxia, dementia,sensory neuropathy, pigmentary retinopathy, and pyramidal signs; (3)myopathy, with exercise intolerance evolving into fixed weakness; and(4) infantile histiocytoid cardiomyopathy.

Complex IV Deficiency or Cytochrome C oxidase deficiency is arespiratory chain disorder with symptoms categorized in two major forms:(1) encephalomyopathy, which is typically normal for the first 6 to 12months of life and then show developmental regression, ataxia, lacticacidosis, optic atrophy, ophthalmoplegia, nystagmus, dystonia, pyramidalsigns, respiratory problems and frequent seizures; and (2) myopathy withtwo main variants: (a) Fatal infantile myopathy—may begin soon afterbirth and accompanied by hypotonia, weakness, lactic acidosis,ragged-red fibers, respiratory failure, and kidney problems; and (b)Benign infantile myopathy—may begin soon after birth and accompanied byhypotonia, weakness, lactic acidosis, ragged-red fibers, respiratoryproblems, but (if the child survives) followed by spontaneousimprovement.

Complex V Deficiency or ATP synthase deficiency is a respiratory chaindisorder including symptoms such as slow, progressive myopathy.

CPEO or Chronic Progressive External Ophthalmoplegia Syndrome is arespiratory chain disorder including symptoms such as visual myopathy,retinitis pigmentosa, or dysfunction of the central nervous system.

In addition to congenital disorders involving inherited defectivemitochondria, acquired mitochondrial dysfunction contributes todiseases, particularly neurodegenerative disorders associated with aginglike Parkinson's, Alzheimer's, and Huntington's Diseases. The incidenceof somatic mutations in mitochondrial DNA rises exponentially with age;diminished respiratory chain activity is found universally in agingpeople. Mitochondrial dysfunction is also implicated in excitoxic,neuronal injury, cerebral vascular accidents such as that associatedwith seizures, stroke and ischemia.

The diseases above appear to be caused by defects in complex I of therespiratory chain. Electron transfer from complex I to the remainder ofthe respiratory chain is mediated by the compound coenzyme Q (also knownas ubiquinone). Oxidized coenzyme Q (CoQ^(ox) or ubiquinone) is reducedby complex I to reduced coenzyme Q (CoQ^(red) or ubiquinol). The reducedcoenzyme Q then transfers its electrons to complex III of therespiratory chain (skipping over complex II), where it is re-oxidized toCoQ^(ox) (ubiquinone). CoQ^(ox) can then participate in furtheriterations of electron transfer.

Very few treatments are available for patients suffering from thesediseases. Recently, the compound idebenone has been proposed fortreatment of Friedreich's ataxia. While the clinical effects ofidebenone have been relatively modest, the complications ofmitochondrial diseases can be so severe that even marginally usefultherapies are preferable to the untreated course of the disease. Anothercompound, MitoQ, has been proposed for treating mitochondrial disorders(see U.S. Pat. No. 7,179,928); clinical results for MitoQ have not yetbeen reported. Administration of coenzyme Q10 (CoQ10) and vitaminsupplements have shown only transient beneficial effects in individualcases of KSS.

Mitochondrial dysfunction has also been implicated in various otherdiseases. Recent studies have suggested that as many 20 percent ofpatients with autism have markers for mitochondrial disease (Shoffner,J. the 60^(th) Annual American Academy of Neurology meeting in Chicago,Apr. 12-19, (2008); Poling, J S et al J. child Neurol. 2008, 21(2)170-2; and Rossignol et al., Am. J. Biochem. & Biotech. (2008) 4,208-217). Some cases of autism have been associated with severaldifferent organic conditions, including bioenergetic metabolismdeficiency suggested by the detection of high lactate levels in somepatients (Coleman M. et al, Autism and Lactic Acidosis, J. Autism DevDisord., (1985) 15: 1-8; Laszlo et al Serum serotonin, lactate andpyruvate levels in infantile autistic children, Clin. Chim. Acta (1994)229:205-207; and Chugani et al., Evidence of altered energy metabolismin autistic children, Progr. Neuropsychopharmacol Biol Psychiat., (1999)23:635-641) and by nuclear magnetic resonance imagining as well aspositron emission tomography scanning which documented abnormalities inbrain metabolism. Although the mechanism of hyperlactacidemia remainsunknown, a likely possibility involves mitochondrial oxidativephosphorylation dysfunction in neuronal cells. A small subset ofautistic patients diagnosed with deficiencies in complex I or III of therespiratory chain have been reported in the literature (see Oliveira,G., Developmental Medicine & Child Neurology (2005) 47 185-189; andFilipek, P A et al., Journal of Autism and Developmental Disorders(2004) 34:615-623). However, in many of the cases of autism where thereis some evidence of mitochondrial dysfunction, there is an absence ofthe classic features associated with mitochondrial disease, such asmitochondrial pathology in muscle biopsy (see Rossignol, D. A. et al.,Am J. Biochem. & Biotech. (2008) 4 (2) 208-217).

Recently, Hayashi et al. (Science Express, published online 3 Apr. 2008;DOI: 10.1126/science. 1156906, and Ishikawa et al., Science (2 May 2008)320 (5876) 661-664) indicated that mitochondrial DNA mutations cancontribute to tumor progression by enhancing the metastatic potential oftumor cells.

The ability to adjust biological production of energy has applicationsbeyond the diseases described above. Various other disorders can resultin suboptimal levels of energy biomarkers (sometimes also referred to asindicators of energetic function), such as ATP levels. Treatments forthese disorders are also needed, in order to modulate one or more energybiomarkers to improve the health of the patient. In other applications,it can be desirable to modulate certain energy biomarkers away fromtheir normal values in an individual that is not suffering from disease.For example, if an individual is undergoing an extremely strenuousundertaking, it can be desirable to raise the level of ATP in thatindividual.

Accordingly, compounds for treatment of mitochondrial disease and/or toadjust biological production of energy have a wide range of practicalapplications.

DISCLOSURE OF THE INVENTION

In one embodiment, the invention embraces compounds of formula I:

where R is selected from the group consisting of:

where the * indicates the point of attachment of R to the remainder ofthe molecule;

-   R¹, R², and R³ are independently selected from hydrogen,    C₁-C₆-alkyl, and O—C₁-C₆-alkyl;-   R⁴ is C₁-C₆-alkyl;-   R⁵ and R⁶ are independently selected from hydrogen, hydroxy, alkoxy,    C₁-C₄₀-alkyl, C₁-C₄₀-alkenyl, C₁-C₄₀-alkynyl, and aryl; where the    alkyl, alkenyl, alkynyl, or aryl groups may optionally be    substituted with    -   —OR¹⁰, —S(O)₀₋₂R¹⁰, —CN, —F, —Cl, —Br, —I, —NR¹⁰R^(10′), oxo,        C₃-C₆-cycloalkyl, aryl, aryl-C₁-C₆-alkyl, heteroaryl,        heterocyclyl, —(O)—R¹¹, —C(O)—C₀-C₆-alkyl-aryl, —C(O)—O—R¹¹,        —(O)—O—C₀-C₆-alkyl-aryl, —(O)—N—R¹¹R^(11′),        —C(O)—N—C₀-C₆-alkyl-aryl, —N—C(O)—R¹¹, —N—C(O)—C₀-C₆-alkyl-aryl;        where the aryl, heteroaryl and heterocyclyl ring substituents        may be further substituted with C₁-C₆-alkyl, C₁-C₆-haloalkyl,        oxo, hydroxy, C₁-C₆-alkoxy, —C(O)—C₁-C₆-alkyl and        —C(O)—O—C₁-C₆-alkyl; and where one of the carbons of the alkyl,        alkenyl, or alkynyl groups may be substituted with a heteroatom        selected from O, N or; or-   R⁵ and R⁶ together with the atom to which they are attached form a    saturated or unsaturated 3-8 membered ring, optionally incorporating    one or more additional, such as one, two, or three, N, O, or S atoms    and optionally substituted with oxo, —OR¹⁰, —SR¹⁰, —CN, —F, —Cl,    —Br, —I, —NR¹⁰R^(10′), C₁-C₆-alkyl, C₁-C₆-haloalkyl;    hydroxy-C₁-C₆-alkyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl,    —C(O)—OH, or —C(O)—O—C₁-C₆-alkyl; or-   R⁵ and R⁶ together with the nitrogen atom to which they are attached    form a N,N′-disubstituted piperazine where the nitrogen substitution    at the 4-position is a group identical to the substitution at the    1-position forming a compound of formula I-Saa or I-Sbb, where R¹,    R², R³, and R⁴ are as defined above:

-   R¹⁰ and R^(10′) are independently selected from the group consisting    of H, C₁-C₆-alkyl, C₁-C₆-haloalkyl, aryl, aryl-C₁-C₆-alkyl,    heteroaryl, heterocyclyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl and    —C(O)—C₁-C₆-alkyl-aryl;-   R¹¹ and R^(11′) are selected from hydrogen and C₁-C₆-alkyl; and-   M and M′ are independently selected from hydrogen, —C(O)—R¹²,    —C(O)—C₁-C₆-alkenyl, —C(O)—C₁-C₆alkynyl, —C(O)-aryl;    —C(O)-heteroaryl, —C(O)O—R¹²; —C(O)NR¹²R¹², —SO₂OR¹²,    —SO₂—C₁-C₆-alkyl, —SO₂-haloC₁-C₆-alkyl; —SO₂-aryl, —SO₂—NR¹²R¹²,    —P(O)(OR¹²)(OR¹²), and C-linked mono or di-peptide, where R¹² is    hydrogen or C₁-C₆-alkyl optionally substituted with —OH, —NH₂,    —NH(C₁-C₄alkyl), —N(C₁-C₄alkyl)₂, —C(O)—OH, —C(O)—O—C₁-C₄-alkyl or    halogen;-   with the proviso that the compound is not    N-(6-amino-3-methyl-2,4-dioxo-1-phenyl-1,2,3,4-tetrahydropyrimidin-5-yl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide    or    N-(6-amino-3-methyl-2,4-dioxo-1-phenyl-1,2,3,4-tetrahydropyrimidin-5-yl)-4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutanamide;-   and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,    metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount or effective amount of one or more compounds of formula I-S asdescribed above.

In one embodiment, the invention embraces compounds of formula I:

where R is selected from the group consisting of:

where the * indicates the point of attachment of R to the remainder ofthe molecule;

-   R¹, R², and R³ are independently selected from hydrogen and    C₁-C₆-alkyl;-   R⁴ is C₁-C₆-alkyl;-   R⁵ and R⁶ are independently selected from hydrogen, hydroxy, alkoxy,    C₁-C₄₀-alkyl, C₁-C₄₀-alkenyl, C₁-C₄₀alkynyl, and aryl; where the    alkyl, alkenyl, alkynyl, or aryl groups may optionally be    substituted with    -   —OR¹⁰, —S(O)₀₋₂R¹⁰, —CN, —F, —Cl, —Br, —I, —NR¹⁰R^(10′), oxo,        C₃-C₆-cycloalkyl, aryl, aryl-C₁-C₆-alkyl, heteroaryl,        heterocyclyl, —(O)—R¹¹, —C(O)—C₀-C₆-alkyl-aryl, —C(O)—O—R¹¹,        —(O)—O—C₀-C₆-alkyl-aryl, —(O)—N—R¹¹R^(11′),        —C(O)—N—C₀-C₆-alkyl-aryl, —N—C(O)—R¹¹, —N—C(O)—C₀-C₆-alkyl-aryl;        where the aryl, heteroaryl and heterocyclyl ring substituents        may be further substituted with C₁-C₆-alkyl, C₁-C₆-haloalkyl,        oxo, hydroxy, C₁-C₆-alkoxy, —C(O)—C₁-C₆-alkyl and        —C(O)—O—C₁-C₆-alkyl; and where one of the carbons of the alkyl,        alkenyl, or alkynyl groups may be substituted with a heteroatom        selected from O, N or; or-   R⁵ and R⁶ together with the atom to which they are attached form a    saturated or unsaturated 3-8 membered ring, optionally incorporating    one or more additional, such as one, two, or three, N, O, or S atoms    and optionally substituted with oxo, —OR¹⁰, —SR¹⁰, —CN, —F, —Cl,    —Br, —I, —NR¹⁰R^(10′), C₁-C₆-alkyl, C₁-C₆-haloalkyl;    hydroxy-C₁-C₆-alkyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl,    —C(O)—OH, or —C(O)—O—C₁-C₆-alkyl; or-   R⁵ and R⁶ together with the nitrogen atom to which they are attached    for a N,N′-disubstituted piperazine where the nitrogen substitution    at the 4-position is a group identical to the substitution at the    1-position forming a compound of formula Iaa or Ibb, where R¹, R²,    R³, and R⁴ are as defined above:

-   R¹⁰ and R^(10′) are independently selected from the group consisting    of H, C₁-C₆-alkyl, C₁-C₆-haloalkyl, aryl, aryl-C₁-C₆-alkyl,    heteroaryl, heterocyclyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl and    —C(O)—C₁-C₆-alkyl-aryl;-   R¹¹ and R^(11′) are selected from hydrogen and C₁-C₆-alkyl; and-   M and M′ are independently selected from hydrogen, —C(O)—R¹²,    —C(O)—C₁-C₆-alkenyl, —C(O)—C₁-C₆alkynyl, —C(O)-aryl;    —C(O)-heteroaryl, —C(O)O—R¹²; —C(O)NR¹²R¹², —SO₂OR¹²,    —SO₂—C₁-C₆-alkyl, —SO₂-haloC₁-C₆-alkyl; —SO₂-aryl, —SO₂—NR¹²R¹²,    —P(O)(OR¹²)(OR¹²), and C-linked mono or di-peptide, where R¹² is    hydrogen or C₁-C₆-alkyl optionally substituted with —OH, —NH₂,    —NH(C₁-C₄alkyl), —N(C₁-C₄alkyl)₂, —C(O)—OH, —C(O)—O—C₁-C₄-alkyl or    halogen;-   with the proviso that the compound is not    N-(6-amino-3-methyl-2,4-dioxo-1-phenyl-1,2,3,4-tetrahydropyrimidin-5-yl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide    or    N-(6-amino-3-methyl-2,4-dioxo-1-phenyl-1,2,3,4-tetrahydropyrimidin-5-yl)-4-(2,5-dihydroxy-3,4,6-trimethylphenyl)-2-hydroxy-2-methylbutanamide;-   and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,    metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount or effective amount of one or more compounds of formula I asdescribed above.

In another embodiment, the invention embraces compounds of formula Ia:

-   R¹, R², and R³ are independently selected from hydrogen and    C₁-C₆-alkyl;-   R⁴ is C₁-C₆-alkyl;-   R⁵ and R⁶ are independently selected from hydrogen, hydroxy, alkoxy,    C₁-C₄₀-alkyl, C₁-C₄₀-alkenyl, C₁-C₄₀alkynyl, and aryl; where the    alkyl, alkenyl, alkynyl, or aryl groups may optionally be    substituted with    -   —OR¹⁰, —S(O)₀₋₂R¹⁰, —CN, —F, —Cl, —Br, —I, —NR¹⁰R^(10′), oxo,        C₃-C₆-cycloalkyl, aryl, aryl-C₁-C₆-alkyl, heteroaryl,        heterocyclyl, —(O)—R¹¹, —C(O)—C₀-C₆-alkyl-aryl, —C(O)—O—R¹¹,        —(O)—O—C₀-C₆-alkyl-aryl, —(O)—N—R¹¹R¹¹,        —C(O)—N—C₀-C₆-alkyl-aryl, —N—C(O)—R¹¹, —N—C(O)—C₀-C₆-alkyl-aryl;        where the aryl, heteroaryl and heterocyclyl ring substituents        may be further substituted with C₁-C₆-alkyl, C₁-C₆-haloalkyl,        oxo, hydroxy, C₁-C₆-alkoxy, —C(O)—C₁-C₆-alkyl and        —C(O)—O—C₁-C₆-alkyl; and where one of the carbons of the alkyl,        alkenyl, or alkynyl groups may be substituted with a heteroatom        selected from O, N or S; or-   R⁵ and R⁶ together with the atom to which they are attached form a    saturated or unsaturated 3-8 membered ring, optionally incorporating    one or more additional, such as one, two, or three, N, O, or S atoms    and optionally substituted with oxo, —OR¹⁰, —SR¹⁰, —CN, —F, —Cl,    —Br, —I, —NR¹⁰R^(10′), C₁-C₆-alkyl, C₁-C₆-haloalkyl;    hydroxy-C₁-C₆-alkyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl,    —C(O)—OH, or —C(O)—O—C₁-C₆-alkyl; or-   R⁵ and R⁶ together with the nitrogen atom to which they are attached    form a N,N′-disubstituted piperazine where the nitrogen substitution    at the 4-position is a group identical to the substitution at the    1-position forming a compound of formula Iaa, where R¹, R², R³, and    R⁴ are as defined above:

-   R¹⁰ and R^(10′) are independently selected from the group consisting    of hydrogen, C₁-C₆-alkyl, C₁-C₆-haloalkyl, aryl, aryl-C₁-C₆-alkyl,    heteroaryl, heterocyclyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl and    —C(O)—C₁-C₆-alkyl-aryl; and-   R¹¹ and R^(11′) are selected from hydrogen and C₁-C₆-alkyl;-   with the proviso that the compound is not    N-(6-amino-3-methyl-2,4-dioxo-1-phenyl-1,2,3,4-tetrahydropyrimidin-5-yl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,    metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R¹, R², and R³ are selected from methyl, ethyl, n-propyl,isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, t-butyl,cyclobutyl, cyclopropyl-methyl, methyl-cyclopropyl, pentyl where thepoint of attachment of the pentyl group to the remainder of the moleculecan be at any location on the pentyl fragment, cyclopentyl, hexyl wherethe point of attachment of the hexyl group to the remainder of themolecule can be at any location on the hexyl fragment, and cyclohexyl;and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment the invention embraces compounds of formula Ia,where one of the R¹, R², and R³ groups is methyl, and the remaininggroups are hydrogen. In another embodiment the invention embracescompounds of formula Ia, where two of the R¹, R², and R³ groups aremethyl, and the remaining group is hydrogen. In another embodiment theinvention embraces compounds of formula Ia, where R¹, R², and R³ aremethyl; and all salts, stereoisomers, mixtures of stereoisomers,prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁴ is selected from methyl, ethyl, n-propyl, i-propyl, orcyclopropyl; and in another embodiment R⁴ is methyl, and all saltsstereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R¹, R², R³, and R⁴ are methyl; and all salts stereoisomers,mixtures of stereoisomers, prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraced compounds of formula Ia,where R⁵ and R⁶, are independently selected from hydrogen, and C₁-C₆alkyl optionally substituted with hydroxy, alkoxy or —C(O)O—C₁-C₆alkyl,and all salts stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ and R⁶ are independently hydrogen or C₁-C₆ alkyl optionallysubstituted with aryl; and a salt, a stereoisomer, or a mixture ofstereoisomers thereof. In another embodiment, one of R⁵ and R⁶ ishydrogen and the other is C₁-C₆ alkyl optionally substituted with aryl;and a salt, a stereoisomer, or a mixture of stereoisomers thereof. Inanother embodiment, R⁵ and R⁶ are hydrogen; and a salt, a stereoisomer,or a mixture of stereoisomers thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is unsubstituted C₁-C₆ alkyl; and in anotherembodiment R⁶ is selected from methyl, ethyl, propyl, isopropyl, butyl,isobutyl, 2-methylbutyl, and cyclopropyl; and all salts stereoisomers,mixtures of stereoisomers, prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl substituted with hydroxy,alkoxy or —C(O)O—C₁-C₆ alkyl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof. Inanother embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl substituted with hydroxy, andall salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof. In another embodiment, theinvention embraces compounds of formula Ia, where R⁵ is hydrogen and R⁶is selected from —(CH₂)₁₋₆—OH; 1-hydroxyprop-2-yl and2-hydroxyprop-1-yl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ and R⁶ are independently selected from C₁-C₆ alkyl substitutedwith hydroxyl; for example R⁵ and R⁶ are substituted with hydroxy ethyl;and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is independently selected from C₁-C₆ alkylsubstituted with —R¹⁰R^(10′), where R¹⁰ and R^(10′) are independentlyselected from the group consisting of hydrogen, C₁-C₆-alkyl,C₁-C₆-haloalkyl, aryl, aryl-C₁-C₆alkyl, heteroaryl, heterocyclyl,—C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl and —C(O)—C₁-C₆-alkyl-aryl andall salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof. In another embodiment, theinvention embraces compounds of formula Ia, where R⁵ is hydrogen and R⁶is independently selected from C₁-C₆ alkyl substituted with —NH₂,—NH(C₁-C₆-alkyl), or —N(C₁-C₆-alkyl)₂, for example where R⁶ isdimethylaminoalkyl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof. Inanother embodiment, the invention embraces pharmaceutically acceptablesalts of compounds of formula Ia, where R⁵ is hydrogen and R⁶ isdimethylaminoethyl; for example hydrochloride or mesylate salts.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted withphenyl, for example benzyl or phenylethyl, and all salts, stereoisomers,mixtures of stereoisomers, prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted withheterocyclyl or heteroaryl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted with anitrogen containing heterocyclyl and all salts, stereoisomers, mixturesof stereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.In another embodiment the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted withpyrrolidinyl, piperidinyl, piperazinyl, or morpholinyl, and all salts,stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted with anitrogen containing heteroaryl, for example imidazolyl, pyridinyl,pyrrolyl, and pyrimidinyl, and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof. Inanother embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted with anitrogen containing heteroaryl, for example imidazol-1-yl orpyridin-2-yl and all salts, stereoisomers, mixtures of stereoisomers,prodrugs, metabolites, solvates, and hydrates thereof. In anotherembodiment, the invention embraces compounds of formula Ia, where R⁵ ishydrogen and R⁶ is 3-(1H-imidazol-1-yl)propyl, pyridin-2-ylmethyl, or2-(pyridin-2-yl)ethyl, and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted withan oxygen or sulfur containing heterocyclyl or heteroaryl, for exampletetrahydropyranyl, tetrahydrofuranyl, tetrahydrothienyl, pyranyl,furanyl, thienyl, benzopyranyl, or benzofuranyl; and all salts,stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ and R⁶ together with the nitrogen atom to which they areattached form an optionally substituted 3 to 8 membered nitrogencontaining heterocyclyl ring, for example an azetidine, a pyrrolidine, apiperidine, a piperazine, a morpholine or an azepane ring; and allsalts, stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ and R⁶ together with the nitrogen atom to which they areattached form piperidin-1-yl, 4-hydroxy-piperidin-1-yl,4-methyl-piperazin-1-yl, 4-benzyl-piperazin-1-yl, and azepan-1-yl andall salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ia,where R⁵ and R⁶ together with the nitrogen atom to which they areattached form a N,N′-disubstituted piperazine where the nitrogensubstitution at the 4-position is a group identical to the substitutionat the 1-position forming a compound of formula Iaa, where R¹, R², R³,and R⁴ are as defined above:

and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of the formulaIb:

-   R¹, R², and R³ are independently selected from hydrogen,    C₁-C₆-alkyl; and-   R⁴ is C₁-C₆-alkyl;-   R⁵ and R⁶ are independently selected from hydrogen, hydroxy, alkoxy,    C₁-C₄₀-alkyl, C₁-C₄₀-alkenyl, C₁-C₄₀-alkynyl, and aryl; where the    alkyl, alkenyl, alkynyl, or aryl groups may optionally be    substituted with    -   —OR¹⁰, —S(O)₀₋₂R¹⁰, —CN, —F, —Cl, —Br, —I, —NR¹⁰R^(10′), oxo,        C₃-C₆-cycloalkyl, aryl, aryl-C₁-C₆-alkyl, heteroaryl,        heterocyclyl, —(O)—R¹¹, —C(O)—C₀-C₆-alkyl-aryl, —C(O)—O—R¹¹,        —(O)—O—C₀-C₆-alkyl-aryl, —(O)—N—R¹¹R^(11′),        —C(O)—N—C₀-C₆-alkyl-aryl, —N—C(O)—R¹¹, —N—C(O)—C₀-C₆-alkyl-aryl;        where the aryl, heteroaryl and heterocyclyl ring substituents        may be further substituted with C₁-C₆-alkyl, C₁-C₆-haloalkyl,        oxo, hydroxy, C₁-C₆-alkoxy, —C(O)—C₁-C₆-alkyl and        —C(O)—O—C₁-C₆-alkyl; and where one of the carbons of the alkyl,        alkenyl, or alkynyl groups may be substituted with a heteroatom        selected from O, N or S; and where-   R⁵ and R⁶ together with the atom to which they are attached form a    saturated or unsaturated 3-8 membered ring, optionally incorporating    one or more additional, such as one, two, or three, N, O, or S atoms    and optionally substituted with oxo, —OR¹⁰, —SR¹⁰, —CN, —F, —Cl,    —Br, —I, —NR¹⁰R^(10′), C₁-C₆-alkyl, C₁-C₆-haloalkyl;    hydroxy-C₁-C₆-alkyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl,    —C(O)—OH, or —C(O)—O—C₁-C₆-alkyl; or-   R⁵ and R⁶ together with the nitrogen atom to which they are attached    form a N,N′-disubstituted piperazine where the nitrogen substitution    at the 4-position is a group identical to the substitution at the    1-position forming a compound of formula Ibb, where R¹, R², R³, and    R⁴ are as defined above:

-   R¹⁰ and R^(10′) are independently selected from the group consisting    of hydrogen, C₁-C₆-alkyl, C₁-C₆-haloalkyl, aryl, aryl-C₁-C₆-alkyl,    heteroaryl, heterocyclyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl and    —C(O)—C₁-C₆-alkyl-aryl;-   R¹¹ and R^(11′) are selected from hydrogen and C₁-C₆-alkyl;-   M and M′ are independently selected from hydrogen, —C(O)—R¹²,    —C(O)—C₁-C₆-alkenyl, —C(O)—C₁-C₆alkynyl, —C(O)-aryl;    —C(O)-heteroaryl, —C(O)O—R¹²; —C(O)NR¹²R¹², —SO₂OR¹²,    —SO₂—C₁-C₆-alkyl, —SO₂-haloC₁-C₆-alkyl; —SO₂-aryl, —SO₂—NR¹²R¹²,    —P(O)(OR¹²)(OR¹²), and C-linked mono or di-peptide, where R¹² is    hydrogen or C₁-C₆-alkyl optionally substituted with —OH, —NH₂,    —NH(C₁-C₄alkyl), —N(C₁-C₄alkyl)₂, —C(O)—OH, —C(O)—O—C₁-C₄-alkyl or    halogen;-   and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,    metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R¹, R², and R³ are selected from methyl, ethyl, n-propyl,isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, t-butyl,cyclobutyl, cyclopropyl-methyl, methyl-cyclopropyl, pentyl where thepoint of attachment of the pentyl group to the remainder of the moleculecan be at any location on the pentyl fragment, cyclopentyl, hexyl wherethe point of attachment of the hexyl group to the remainder of themolecule can be at any location on the hexyl fragment and cyclohexyl;and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where one of the R¹, R², and R³ groups is methyl, and the remaininggroups are hydrogen. In another embodiment the invention embracescompounds of formula Ib, where two of the R¹, R², and R³ groups aremethyl, and the remaining group is hydrogen. In another embodiment theinvention embraces compounds of formula Ib, where R¹, R², and R³ aremethyl; and all salts, stereoisomers, mixtures of stereoisomers,prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁴ is selected from methyl, ethyl, n-propyl, i-propyl, orcyclopropyl; and in another embodiment R⁴ is methyl, and all saltsstereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R¹, R², R³, and R⁴ are methyl; and all salts stereoisomers,mixtures of stereoisomers, prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ and R⁶ are independently selected from hydrogen, and C₁-C₆alkyloptionally substituted with hydroxy, alkoxy or —C(O)O—C₁-C₆ alkyl, andall salts stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ and R⁶ are independently hydrogen or C₁-C₆ alkyl optionallysubstituted with aryl; and a salt, a stereoisomer, or a mixture ofstereoisomers thereof. In another embodiment, one of R⁵ and R⁶ ishydrogen and the other is C₁-C₆ alkyl optionally substituted with aryl;and a salt, a stereoisomer, or a mixture of stereoisomers thereof. Inanother embodiment, R⁵ and R⁶ are hydrogen; and a salt, a stereoisomer,or a mixture of stereoisomers thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is unsubstituted C₁-C₆ alkyl, and in anotherembodiment R⁶ is selected from methyl, ethyl, propyl, isopropyl, butyl,isobutyl, 2-methylbutyl, cyclopropyl and all salts stereoisomers,mixtures of stereoisomers, prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl substituted with hydroxy,alkoxy or —C(O)O—C₁-C₆ alkyl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof. Inanother embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl substituted with hydroxy, andall salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof. In another embodiment, theinvention embraces compounds of formula Ib, when R⁵ is hydrogen and R⁶is selected from —(CH₂)₁₋₆—OH; 1-hydroxyprop-2-yl and2-hydroxyprop-1-yl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ and R⁶ are independently selected from C₁-C₆ alkyl substitutedwith hydroxyl; for example R⁵ and R⁶ are substituted with hydroxyethyl;and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is independently selected from C₁-C₆ alkylsubstituted with —NR¹⁰R^(10′) where R¹⁰ and R^(10′) are independentlyselected from the group consisting of hydrogen, C₁-C₆-alkyl,C₁-C₆-haloalkyl, aryl, aryl-C₁-C₆-alkyl, heteroaryl, heterocyclyl,—C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl and —C(O)—C₁-C₆-alkyl-aryl; andall salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ibwhere R⁵ is hydrogen and R⁶ is independently selected from C₁-C₆ alkylsubstituted with —NH₂, —NH(C₁-C₆-alkyl), or —N(C₁-C₆-alkyl)₂, forexample where R⁶ is dimethylaminoalkyl such as dimethylaminoethyl; andall salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted withphenyl, for example benzyl or phenylethyl, and all salts, stereoisomers,mixtures of stereoisomers, prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆alkyl optionally substituted withheterocyclyl or heteroaryl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted with anitrogen containing heterocyclyl, and all salts, stereoisomers, mixturesof stereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.In another embodiment the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted withpyrrolidinyl, piperidinyl, piperazinyl, or morpholinyl, and all salts,stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted with anitrogen containing heteroaryl, for example imidazolyl, pyridinyl,pyrrolyl, and pyrimidinyl and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl optionally substituted withan oxygen or sulfur containing heterocyclyl or heteroaryl, for exampletetrahydropyranyl, tetrahydrofuranyl, tetrahydrothienyl, pyranyl,furanyl or thienyl; and all salts, stereoisomers, mixtures ofstereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ and R⁶ together with the nitrogen atom to which they areattached form an optionally substituted 3 to 8-membered nitrogencontaining heterocyclyl ring, for example an azetidine, a pyrrolidine, apiperidine, a piperazine, a morpholine or an azepane ring; and allsalts, stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ and R⁶ together with the nitrogen atom to which they areattached form piperidin-1-yl, 4-hydroxy-piperidin-1-yl,4-methyl-piperazin-1-yl, 4-benzyl-piperazin-1-yl, and azepan-1-yl andall salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R⁵ and R⁶ together with the nitrogen atom to which they areattached form a N,N′-disubstituted piperazine where the nitrogensubstitution at the 4-position is a group identical to the substitutionat the 1 position forming a compound of formula Ibb, where R¹, R², R³,and R⁴ are as defined above:

and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where M and M′ are selected from hydrogen, —C(O)—H or —C(O)—C₁-C₆-alkyl,for example hydrogen or acetyl, and all salts, stereoisomers, mixturesof stereoisomers, prodrugs, metabolites, solvates, and hydrates thereof.

In another embodiment, the invention embraces compounds of formula Ib,where R¹, R², R³, and R⁴ are methyl and M and M′ are hydrogen orC(O)—R¹², and a salt, a stereoisomer, or a mixture of stereoisomers. Inanother embodiment, the invention embraces compounds of formula Ib,where R¹, R², R³, and R⁴ are methyl and M and M′ are hydrogen or acetyl,and a salt, a stereoisomer, or a mixture of stereoisomers.

In another embodiment, the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount of one or more compounds of formula I, formula Ia, formula Iaa,formula Ib, or formula Ibb; or of the embodiments of formula I, formulaIa, formula Iaa, formula Ib, or formula Ibb; and all salts,stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraced a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount of one or more compounds of formula Ia, where R¹, R², R³, and R⁴are independently selected from —C₁-C₄ alkyl; and all salts,stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment, the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount of a stereoisomer compound of formula Ia, where R¹, R², R³, andR⁴ are independently selected from —C₁-C₄ alkyl; and where R⁴ has an (R)configuration; and prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount of a stereoisomer compound of formula Ia, where R¹, R², R³, andR⁴ are independently selected from —C₁-C₄ alkyl; and where R⁴ has an (S)configuration; and prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount or effective amount of one or more compounds of formula Ib, whereR¹, R², R³, and R⁴ are independently selected from —C₁-C₄ alkyl; and allsalts, stereoisomers, mixtures of stereoisomers, prodrugs, metabolites,solvates, and hydrates thereof.

In another embodiment the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount of a stereoisomer compound of formula Ib, where R¹, R², R³, andR⁴ are independently selected from —C₁-C₄ alkyl; and where R⁴ has an (R)configuration; and prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces a method of treating orsuppressing a mitochondrial disorder, modulating one or more energybiomarkers, normalizing one or more energy biomarkers, or enhancing oneor more energy biomarkers, by administering a therapeutically effectiveamount of a stereoisomer compound of formula Ib, where R¹, R², R³, andR⁴ are independently selected from —C₁-C₄ alkyl; and where R⁴ has an (S)configuration; and prodrugs, metabolites, solvates, and hydratesthereof.

In another embodiment, the invention embraces compounds of formula I,selected from:

-   2-hydroxy-N-isopropyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-3-methyl-4-oxo-4-(piperidin-1-yl)butyl-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(4-(azepan-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   N-hexyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-tert-butyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N,N,2-trimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-ethyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-benzyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-propyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(cyclopropylmethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-phenethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(3-hydroxypropyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-isopentyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-cyclopropyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-hydroxy-N-isobutyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-ethyl-2-hydroxy-N,2-dimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxybutyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(5-hydroxypentyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-methoxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(1-hydroxypropan-2-yl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (R)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   methyl    2-(2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamido)acetate;-   N-(3-1H-imidazol-1-yl)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-(2-hydroxyethyoxy)ethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(pyridin-2-ylmethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(2-(pyridin-2-yl)ethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(3-(2-oxopyrrolidin-1-yl)propyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(6-hydroxyhexyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-3-methyl-4-(4-methylpiperazin-1-yl)-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(4-(4-benzylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-hydroxy-2-methyl-N-((tetrahydrofuran-2-yl)methyl)-4-oxobutyl)-2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(3-morpholinopropyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-methoxy-N,2-dimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N,N-bis(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxyphenethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-dimethylamino)propyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   6,6′-(4,4′-(piperazine-1,4-diyl)bis(3-hydroxy-3-methyl-4-oxobutane-4,1-diyl))bis(2,3,5-trimethylcyclohexa-2,5-diene-1,4-dione);-   N-butyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxyethyl)-N,2-dimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N,N-diethyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   tert-butyl    2-(2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamido)ethylcarbamate;-   2-hydroxy-2-methyl-N-(pyridin-4-ylmethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(pyridin-3-ylmethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(3-(methylsulfonyl)propyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamido)acetic    acid;-   2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-(3,5,6-trimethylcyclohexa-2,5-dienyl-1,4-dione;-   2-(4-(4-fluoropiperidin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-(3,5,6-trimethylcyclohexa-2,5-dienyl-1,4-dione;-   2-(4-(4,4-difluoropiperidin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-(3,5,6-trimethylcyclohexa-2,5-dienyl-1,4-dione;-   2-(3-hydroxy-3-methyl-4-oxo-4-(piperazin-1-yl)butyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   tert-butyl    4-(2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoyl)piperazine-1-carboxylate;-   2-(4-(4-benzoylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-4-(4-isopropylpiperazine-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(4-(4-(cyclopropanecarbonyl)piperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (S)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (S)-2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   N-(2-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-methoxyphenyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;    and all salts, stereoisomers, mixtures of stereoisomers, prodrugs,    metabolites, solvates, and hydrates thereof.

In other embodiments, including any of the foregoing embodiments, themitochondrial disorder is selected from the group consisting ofinherited mitochondrial diseases; Myoclonic Epilepsy with Ragged RedFibers (MERRF); Mitochondrial Myopathy, Encephalopathy, Lactacidosis,and Stroke (MELAS); Leber's Hereditary Optic Neuropathy (LHON); LeighDisease; Kearns-Sayre Syndrome (KSS); Friedreich's Ataxia (FA); othermyopathies; cardiomyopathy; encephalomyopathy; renal tubular acidosis;neurodegenerative diseases; Parkinson's Disease; Alzheimer's Disease;Amyotrophic Lateral Sclerosis (ALS); motor neuron diseases; otherneurological diseases; epilepsy; genetic diseases; Huntington's Disease;mood disorders; schizophrenia; bipolar disorder; age-associateddiseases; cerebral vascular accidents, macular degeneration; diabetes;and cancer.

In another embodiment, including any of the foregoing embodiments, themitochondrial disorder is a mitochondrial respiratory chain disorder. Ina particular embodiment, the mitochondrial respiratory chain disorder isa respiratory protein chain disorder. In another particular embodiment,the disorder is CoQ10 deficiency.

In another embodiment, including any of the foregoing embodiments, themitochondrial disorder is selected from the group consisting ofinherited mitochondrial diseases; Myoclonic Epilepsy with Ragged RedFibers (MERRF); Mitochondrial Myopathy, Encephalopathy, Lactacidosis,and Stroke (MELAS); Liber's Hereditary Optic Neuropathy (LHON); LeighDisease; Kearns-Sayre Syndrome (KSS); Friedreich's Ataxia (FA).

In another embodiment of the invention, including any of the foregoingembodiments, the mitochondrial disorder is Friedreich's Ataxia (FA). Inanother embodiment of the invention, the mitochondrial disorder isLeber's Hereditary Optic Neuropathy (LHON). In another embodiment of theinvention, including any of the foregoing embodiments, the mitochondrialdisorder is mitochondrial myopathy, encephalopathy, lactacidosis, andstroke (MELAS). In another embodiment of the invention, including any ofthe foregoing embodiments, the mitochondrial disorder is Kearns-SayreSyndrome (KSS). In another embodiment of the invention, themitochondrial disorder is Myoclonic Epilepsy with Ragged Red Fibers(MERRF). In another embodiment of the invention, including any of theforegoing embodiments, the disorder is Parkinson's Disease. In anotherembodiment of the invention, including any of the foregoing embodiments,the disorder is Huntington's Disease. In another embodiment of theinvention including any of the foregoing embodiments, the disorder isamyotrophic lateral sclerosis (ALS). In yet another embodiment of theinvention including any of the foregoing embodiments, the disorders arecerebral vascular accidents, such as stroke.

In another embodiment of the invention, including any of the foregoingembodiments, the compounds described herein are administered to subjectssuffering from a mitochondrial disorder to modulate one or more ofvarious energy biomarkers, including, but not limited to, lactic acid(lactate) levels, either in whole blood, plasma, cerebrospinal fluid, orcerebral ventricular fluid; pyruvic acid (pyruvate) levels, either inwhole blood, plasma, cerebrospinal fluid, or cerebral ventricular fluid;lactate/pyruvate ratios, either in whole blood, plasma, cerebrospinalfluid, or cerebral ventricular fluid; phosphocreatine levels, NADH(NADH+H⁺) or NADPH (NADPH+H⁺) levels; NAD or NADP levels; ATP levels;reduced coenzyme Q (CoQ^(red)) levels; oxidized coenzyme Q (CoQ^(ox))levels; total coenzyme Q (CoQ^(tot)) levels; oxidized cytochrome Clevels; reduced cytochrome C levels; oxidized cytochrome C/reducedcytochrome C ratio; acetoacetate levels; beta-hydroxy butyrate levels;acetoacetate/beta-hydroxy butyrate ratio; 8-hydroxy-2′-deoxyguanosine(8-OHdG) levels; levels of reactive oxygen species; oxygen consumption(VO2), carbon dioxide output (VCO2), respiratory quotient (VCO2/VO2),and to modulate exercise intolerance (or conversely, modulate exercisetolerance) and to modulate anaerobic threshold. Energy biomarkers can bemeasured in whole blood, plasma, cerebrospinal fluid, cerebroventricularfluid, arterial blood, venous blood, or any other body fluid, body gas,or other biological sample useful for such measurement. In oneembodiment, the levels are modulated to a value within about 2 standarddeviations of the value in a healthy subject. In another embodiment, thelevels are modulated to a value within about 1 standard deviation of thevalue in a healthy subject. In another embodiment, the levels in asubject are changed by at least about 10% above or below the level inthe subject prior to modulation. In another embodiment, the levels arechanged by at least about 20% above or below the level in the subjectprior to modulation. In another embodiment, the levels are changed by atleast about 30% above or below the level in the subject prior tomodulation. In another embodiment, the levels are changed by at leastabout 40% above or below the level in the subject prior to modulation.In another embodiment, the levels are changed by at least about 50%above or below the level in the subject prior to modulation. In anotherembodiment, the levels are changed by at least about 75% above or belowthe level in the subject prior to modulation. In another embodiment, thelevels are changed by at least about 100% above or at least about 90%below the level in the subject prior to modulation.

In another embodiment of the invention, including any of the foregoingembodiments, the compounds described herein are administered to treatsubjects suffering from pervasive development disorders selected fromAutistic Disorder, Asperger's Disorder, Childhood DisintegrativeDisorder (CDD), Rett's Disorder, and Pervasive DevelopmentalDisorder—Not Otherwise Specified (PDD-NOS). In another embodiment, thedisorder is Austistic Disorder.

In another embodiment, including any of the foregoing embodiments, thesubject or subjects in which a method of treating or suppressing amitochondrial disorder, modulating one or more, energy biomarkers,normalizing one or more energy biomarkers, or enhancing one or moreenergy biomarkers is performed is/are selected from the group consistingof subjects undergoing strenuous or prolonged physical activity;subjects with chronic energy problems; subjects with chronic respiratoryproblems; pregnant females; pregnant females in labor; neonates;premature neonates; subjects exposed to extreme environments; subjectsexposed to hot environments; subjects exposed to cold environments;subjects exposed to environments with lower-than-average oxygen content;subjects exposed to environments with higher-than-average carbon dioxidecontent: subjects exposed to environments with higher-than-averagelevels of air pollution; airline travelers; flight attendants; subjectsat elevated altitudes; subjects living in cities with lower-than-averageair quality; subjects working in enclosed environments where air qualityis degraded; subjects with lung diseases; subjects withlower-than-average lung capacity; tubercular patients; lung cancerpatients; emphysema patients; cystic fibrosis patients; subjectsrecovering from surgery; subjects recovering from illness; elderlysubjects; elderly subjects experiencing decreased energy; subjectssuffering from chronic fatigue; subjects suffering from chronic fatiguesyndrome; subjects undergoing acute trauma; subjects in shock; subjectsrequiring acute oxygen administration; subjects requiring chronic oxygenadministration; or other subjects with acute, chronic, or ongoing energydemands who can benefit from enhancement of energy biomarkers.

In another embodiment, the invention embraces one or more compounds offormula I, Ia, Ib, Iaa, and/or Ibb, in combination with apharmaceutically acceptable excipient, carrier, or vehicle.

In another embodiment, the invention embraces the use of one or morecompounds of formula I, Ia, Ib, Iaa, and/or Ibb, in the therapy ofmitochondrial disease. In another embodiment, the invention embraces theuse of one or more compounds of formula I, Ia, Ib, Iaa, and/or Ibb inthe manufacture of a medicament for use in therapy of mitochondrialdisease.

For all of the compounds and methods described above, the quinone formcan also be used in its reduced (hydroquinone) form when desired.Likewise, the hydroquinone form can also be used in its oxidized(quinone) form when desired.

MODES FOR CARRYING OUT THE INVENTION

The invention embraces compounds useful in treating or suppressingmitochondrial disorder's, and methods of using such compounds formodulation of energy biomarkers. The redox active therapeutics fortreatment or suppression of mitochondrial diseases and associatedaspects of the invention are described in more detail herein.

By “subject,” “individual,” or “patient” is meant an individualorganism, preferably a vertebrate, more preferably a mammal, mostpreferably a human.

“Treating” a disease with the compounds and methods discussed herein isdefined as administering one or more of the compounds discussed herein,with or without additional therapeutic agents, in order to reduce oreliminate either the disease or one or more symptoms of the disease, orto retard the progression of the disease or of one or more symptoms ofthe disease, or to reduce the severity of the disease or of one or moresymptoms of the disease. “Suppression” of a disease with the compoundsand methods discussed herein is defined as administering one or more ofthe compounds discussed herein, with or without additional therapeuticagents, in order to suppress the clinical manifestation of the disease,or to suppress the manifestation of adverse symptoms of the disease. Thedistinction between treatment and suppression is that treatment occursafter adverse symptoms of the disease are manifest in a subject, whilesuppression occurs before adverse symptoms of the disease are manifestin a subject. Suppression may be partial, substantially total, or total.Because many of the mitochondrial disorders are inherited, geneticscreening can be used to identify patients at risk of the disease. Thecompounds and methods of the invention can then be administered toasymptomatic patients at risk of developing the clinical symptoms of thedisease, in order to suppress the appearance of any adverse symptoms.“Therapeutic use” of the compounds discussed herein is defined as usingone or more of the compounds discussed herein to treat or suppress adisease, as defined above. An “effective amount” of a compound is anamount of the compound sufficient to modulate, normalize, or enhance oneor more energy biomarkers (where modulation, normalization, andenhancement are defined below). A “therapeutically effective amount” ofa compound is an amount of the compound, which, when administered to asubject, is sufficient to reduce or eliminate either a disease or one ormore symptoms of a disease, or to retard the progression of a disease orof one or more symptoms of a disease, or to reduce the severity of adisease or of one or more symptoms of a disease, or to suppress theclinical manifestation of a disease, or to suppress the manifestation ofadverse symptoms of a disease. A therapeutically effective amount can begiven in one or more administrations. An “effective amount” of acompound embraces both a therapeutically effective amount, as well as anamount effective to modulate, normalize, or enhance one or more energybiomarkers in a subject.

“Modulation” of, or to “modulate,” an energy biomarker means to changethe level of the energy biomarker towards a desired value, or to changethe level of the energy biomarker in a desired direction (e.g., increaseor decrease). Modulation can include, but is not limited to,normalization and enhancement as defined below.

“Normalization” of, or to “normalize,” an energy biomarker is defined aschanging the level of the energy biomarker from a pathological valuetowards a normal value, where the normal value of the energy biomarkercan be 1) the level of the energy biomarker in a healthy person orsubject, or 2) a level of the energy biomarker that alleviates one ormore undesirable symptoms in the person or subject. That is, tonormalize an energy biomarker which is depressed in a disease statemeans to increase the level of the energy biomarker towards the normal(healthy) value or towards a value which alleviates an undesirablesymptom; to normalize an energy biomarker which is elevated in a diseasestate means to decrease the level of the energy biomarker towards thenormal (healthy) value or towards a value which alleviates anundesirable symptom.

“Enhancement” of, or to “enhance,” energy biomarkers means tointentionally change the level of one or more energy biomarkers awayfrom either the normal value, or the value before enhancement, in orderto achieve a beneficial or desired effect. For example, in a situationwhere significant energy demands are placed on a subject, it may bedesirable to increase the level of ATP in that subject to a level abovethe normal level of ATP in that subject. Enhancement can also be ofbeneficial effect in a subject suffering from a disease or pathologysuch as a mitochondrial disease, in that normalizing an energy biomarkermay not achieve the optimum outcome for the subject; in such cases,enhancement of one or more energy biomarkers can be beneficial, forexample, higher-than-normal levels of ATP, or lower-than-normal levelsof lactic acid (lactate) can be beneficial to such a subject.

By modulating, normalizing, or enhancing the energy biomarker Coenzyme Qis meant modulating, normalizing, or enhancing the variant or variantsof Coenzyme Q which is predominant in the species of interest. Forexample, the variant of Coenzyme Q which predominates in humans isCoenzyme Q10. If a species or subject has more than one variant ofCoenzyme Q present in significant amounts (i.e., present in amountswhich, when modulated, normalized, or enhanced, can have a beneficialeffect on the species or subject), modulating, normalizing, or enhancingCoenzyme Q can refer to modulating, normalizing or enhancing any or allvariants of Coenzyme Q present in the species or subject.

While the compounds described herein can occur and can be used as theneutral (non-salt) compound, the description is intended to embrace allsalts of the compounds described herein, as well as methods of usingsuch salts of the compounds. In one embodiment, the salts of thecompounds comprise pharmaceutically acceptable salts. Pharmaceuticallyacceptable salts are those salts which can be administered as drugs orpharmaceuticals to humans and/or animals and which, upon administration,retain at least some of the biological activity of the free compound(neutral compound or non-salt compound). The desired salt of a basiccompound may be prepared by methods known to those of skill in the artby treating the compound with an acid. Examples of inorganic acidsinclude, but are not limited to, hydrochloric acid, hydrobromic acid,sulfuric acid, nitric acid, and phosphoric acid. Examples of organicacids include, but are not limited to, formic acid, acetic acid,propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid,malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid,benzoic acid, cinnamic acid, mandelic acid, sulfonic acids, andsalicylic acid. Salts of basic compounds with amino acids, such asaspartate salts and glutamate salts, can also be prepared. The desiredsalt of an acidic compound can be prepared by methods known to those ofskill in the art by treating the compound with a base. Examples ofinorganic salts of acid compounds include, but are not limited to,alkali metal and alkaline earth salts, such as sodium salts, potassiumsalts, magnesium salts, and calcium salts; ammonium salts; and aluminumsalts. Examples of organic salts of acid compounds include, but are notlimited to, procaine, dibenzylamine, N-ethylpiperidine,N,N-dibenzylethylenediamine, and triethylamine salts. Salts of acidiccompounds with amino acids, such as lysine salts, can also be prepared.Additional salts particularly useful for pharmaceutical preparations aredescribed in Berge S. M. et al., “Pharmaceutical salts,” J. Pharm. Sci.1977 January; 66(1):1-19.

The invention also includes all stereoisomers of the compounds,including diastereomers and enantiomers. The invention also includesmixtures of stereoisomers in any ratio, including, but not limited to,racemic mixtures. Unless stereochemistry is explicitly indicated in astructure, the structure is intended to embrace all possiblestereoisomers of the compound depicted. If stereochemistry is explicitlyindicated for one portion or portions of a molecule, but not for anotherportion or portions of a molecule, the structure is intended to embraceall possible stereoisomers for the portion or portions wherestereochemistry is not explicitly indicated.

For the purpose of the invention, the compounds of Formula I, and allother compounds disclosed herein, either genetically or specifically,include derivatives wherein one or more hydrogen atoms have beenreplaced by a hydrogen isotope, for example by deuterium.

The compounds can be administered in prodrug form. Prodrugs arederivatives of the compounds, which are themselves relatively inactivebut which convert into the active compound when introduced into thesubject in which they are used by a chemical or biological process invivo, such as an enzymatic conversion. Suitable prodrug formulationsinclude, but are not limited to, peptide conjugates of the compounds ofthe invention and esters of compounds of the inventions. Furtherdiscussion of suitable prodrugs is provided in H. Bundgaard, Design ofProdrugs, New York: Elsevier, 1985; in R. Silverman, The OrganicChemistry of Drug Design and Drug Action, Boston: Elsevier. 2004: in R.L. Juliano (ed.), Biological Approaches to the Controlled Delivery ofDrugs (Annals of the New York Academy of Sciences, v. 507), New York:New York Academy of Sciences, 1987; and in E. B. Roche (ed.), Design ofBiopharmaceutical Properties Through Prodrugs and Analogs (Symposiumsponsored by Medicinal Chemistry Section, APhA Academy of PharmaceuticalSciences, November 1976 national meeting, Orlando, Florida), Washington:The Academy, 1977.

Metabolites of the compounds are also embraced by the invention.

“C₁-C₆ alkyl” is intended to embrace a saturated linear, branched,cyclic, or a combination thereof, hydrocarbon of 1 to 6 carbon atoms.Examples of “C₁-C₆ alkyl” are methyl, ethyl, n-propyl, isopropyl,cyclopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, cyclobutyl,cyclopropyl-methyl, metyl-cyclopropyl, pentyl where the point ofattachment of the pentyl group to the remainder of the molecule can beat any location on the pentyl fragment, cyclopentyl, hexyl where thepoint of attachment of the hexyl group to the remainder of the moleculecan be at any location on the hexyl fragment, and cyclohexyl.

“Halogen” or “halo” designates fluoro, chloro, bromo, and iodo.

“C₁-C₆ haloalkyl” is intended to embrace any C₁-C₆ alkyl substituenthaving at least one halogen substituent; the halogen can be attached viaany valence on the C₁-C₆ alkyl group. Some examples of C₁-C₆ haloalkylis —CF₃, —CCl₃, —CHF₂, —CHCl₂, —CHBr2, —CH2F, —CH2Cl.

The term “aryl” is intended to embrace an aromatic cyclic hydrocarbongroup of from 6 to 20 carbon atoms having a single ring (e.g., phenyl)or multiple condensed (fused) rings (e.g., naphthyl or anthryl).

The term “Friedreich's Ataxia” is intended to embrace other ataxias, andis also sometimes referred to as hereditary ataxia, familiar ataxia, orFriedreich's tabes.

The terms “heterocycle”, “heterocyclic”, “heterocyclo”, and“heterocyclyl” is intended to encompass a monovalent, saturated, orpartially unsaturated, carbocyclic radical having one or more ringsincorporating one, two, three or four heteroatoms within the ring(chosen from nitrogen, oxygen, and/or sulfur). Examples of heterocyclesinclude morpholine, piperidine, piperazine, thiazolidine, pyrazolidine,pyrazoline, imidazolidine, pyrrolidine, tetrahydropyran,tetrahydrofuran, quinuclidine, and the like.

The terms “heteroaryl”, is intended to encompass a monovalent aromatic,carbocyclic radical having one or more rings incorporating one, two,three or four heteroatoms within the ring (chosen from nitrogen, oxygen,and/or sulfur). Examples of heteroaryl include pyridine, pyrazine,imidazoline, thiazole, isothiazole, pyrazine, triazine, pyrimidine,pyridazine, pyrazole, thiophene, pyrrole, pyran, furan, indole,quinoline, quinazoline, benzimidazole, benzothiophene, benzofuran,benzoxazole, benzothiazole, benzotriazole, imidazo-pyridines,pyrazolo-pyridines, pyrazolo-pyrazine, acridine, carbazole, and thelike.

The terms “Parkinson's”, (also called “Parkinsonism” and “Parkinsoniansyndrome”) (“PD”) is intended to include not only Parkinson's diseasebut also drug-induced Parkinsonism and post-encephalitic Parkinsonism.Parkinson's disease is also known as paralysis agitans or shaking palsy.It is characterized by tremor, muscular rigidity and loss of posturalreflexes. The disease usually progresses slowly with intervals of 10 to20 years elapsing before the symptoms cause incapacity. Due to theirmimicry of effects of Parkinson's disease, treatment of animals withmethamphetamine or MPTP has been used to generate models for Parkinson'sdisease. These animal models have been used to evaluate the efficacy ofvarious therapies for Parkinson's disease.

Diseases Amenable to Treatment or Suppression with Compounds and Methodsof the Invention

A variety of diseases are believed to be caused or aggravated bymitochondrial disorders and impaired energy processing, and can betreated or suppressed using the compounds and methods of the invention.Such diseases include, but are not limited to, inherited mitochondrialdiseases, such as Myoclonic Epilepsy with Ragged Red Fibers (MERRF),Mitochondrial Myopathy, Encephalopathy, Lactacidosis, and Stroke(MELAS), Leber's Hereditary Optic Neuropathy (LHON, also referred to asLeber's Disease, Leber's Optic Atrophy (LOA), or Leber's OpticNeuropathy (LON)), Leigh Disease or Leigh Syndrome, Kearns-SayreSyndrome (KSS), Friedreich's Ataxia (FA), other myopathies (includingcardiomyopathy and encephalomyopathy), and renal tubular acidosis;neurodegenerative diseases, such as Parkinson's disease, Alzheimer'sdisease, amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig'sdisease), motor neuron diseases; other neurological diseases such asepilepsy; genetic diseases such as Huntington's Disease (which is also aneurological disease); mood disorders such as schizophrenia and bipolardisorder; cerebral vascular accidents such as stroke, and certainage-associated diseases, particularly diseases for which CoQ10 has beenproposed for treatment, such as macular degeneration, diabetes, andcancer. Mitochondrial dysfunction is also implicated in excitoxic,neuronal injury, such as that associated with seizures, stroke andischemia. Mitochondrial dysfunction is also implicated in certainpatients suffering from pervasive development disorders selected fromAutistic Disorder, Asperger's Disorder, Childhood DisintegrativeDisorder (CDD), Rett's Disorder, and Pervasive DevelopmentalDisorder—Not Otherwise Specified (PDD-NOS), and those disorders can alsobe treated or suppressed using the compounds and methods of theinvention.

Clinical Assessment of Mitochondrial Dysfunction and Efficacy of Therapy

Several readily measurable clinical markers are used to assess themetabolic state of patients with mitochondrial disorders. These markerscan also be used as indicators of the efficacy of a given therapy, asthe level of a marker is moved from the pathological value to thehealthy value. These clinical markers include, but are not limited to,one or more of the previously discussed energy biomarkers, such aslactic acid (lactate) levels, either in whole blood, plasma,cerebrospinal fluid, or cerebral ventricular fluid; pyruvic acid(pyruvate) levels, either in whole blood, plasma, cerebrospinal fluid,or cerebral ventricular fluid; lactate/pyruvate ratios, either in wholeblood, plasma, cerebrospinal fluid, or cerebral ventricular fluid;phosphocreatine levels, NADH (NADH+H⁺) or NADPH (NADPH+H⁺) levels; NADor NADP levels; ATP levels; anaerobic threshold; reduced coenzyme Q(CoQ^(red)) levels; oxidized coenzyme Q (CoQ^(ox)) levels; totalcoenzyme Q (CoQ^(tot)) levels; oxidized cytochrome C levels; reducedcytochrome C levels; oxidized cytochrome C/reduced cytochrome C ratio;acetoacetate levels, β-hydroxy butyrate levels, acetoacetate/β-hydroxybutyrate ratio, 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels; levels ofreactive oxygen species; and levels of oxygen consumption (VO2), levelsof carbon dioxide output (VCO2), and respiratory quotient (VCO2/VO2).Several of these clinical markers are measured routinely in exercisephysiology laboratories, and provide convenient assessments of themetabolic state of a subject. In one embodiment of the invention, thelevel of one or more energy biomarkers in a patient suffering from amitochondrial disease, such as Friedreich's ataxia, Leber's hereditaryoptic neuropathy, MELAS, or KSS, is improved to within two standarddeviations of the average level in a healthy subject. In anotherembodiment of the invention, the level of one or more of these energybiomarkers in a patient suffering from a mitochondrial disease, such asFriedreich's ataxia, Leber's hereditary optic neuropathy, MELAS, or KSSis improved to within one standard deviation of the average level in ahealthy subject. Exercise intolerance can also be used as an indicatorof the efficacy of a given therapy, where an improvement in exercisetolerance (i.e., a decrease in exercise intolerance) indicates efficacyof a given therapy.

Several metabolic biomarkers have already been used to evaluate efficacyof CoQ10, and these metabolic biomarkers can be monitored as energybiomarkers for use in the methods of the current invention. Pyruvate, aproduct of the anaerobic metabolism of glucose, is removed by reductionto lactic acid in an anaerobic setting or by oxidative metabolism, whichis dependent on a functional mitochondrial respiratory chain.Dysfunction of the respiratory chain may lead to inadequate removal oflactate and pyruvate from the circulation and elevated lactate/pyruvateratios are observed in mitochondrial cytopathies (see Scriver C R, Themetabolic and molecular bases of inherited disease, 7th ed., New York:McGraw-Hill, Health Professions Division, 1995; and Munnich et al., J.Inherit. Metab. Dis. 15(4):448-55 (1992)). Blood lactate/pyruvate ratio(Chariot et al., Arch. Pathol. Lab. Med. 118(71:695-7 (1994)) is,therefore, widely used as a noninvasive test for detection ofmitochondrial cytopathies (see again Scriver C R, The metabolic andmolecular bases of inherited disease, 7th ed., New York: McGraw-Hill,Health Professions Division, 1995; and Munnich et al., J. Inherit.Metab. Dis. 15(4):448-55 (1992)) and toxic mitochondrial myopathies(Chariot et al., Arthritis Rheum. 37(4):583-6 (1994)). Changes in theredox state of liver mitochondria can be investigated by measuring thearterial ketone body ratio (acetoacetate/3-hydroxybutyrate: AKBR) (Uedaet al., J. Cardiol. 29(2):95-102 (1997)). Urinary excretion of8-hydroxy-2′-deoxyguanosine (8-OHdG) often has been used as a biomarkerto assess the extent of repair of ROS-induced DNA damage in bothclinical and occupational settings (Erhola et al., FEBS Lett.409(2):287-91 (1997); Honda et al., Leuk. Res. 24(6):461-8 (2000);Pilger et al., Free Radic. Res. 35(3):273-80 (2001); Kim et al. EnvironHealth Perspect 112(6):666-71 (2004)).

Magnetic resonance spectroscopy (MRS) has been useful in the diagnosesof mitochondrial cytopathy by demonstrating elevations in cerebrospinalfluid (CSF) and conical white matter lactate using proton MRS (1H-MRS)(Kaufmann et al., Neurology 62(8): 1297-302 (2004)). Phosphorous MRS(31P-MRS) has been used to demonstrate low levels of corticalphosphocreatine (PCr) (Matthews et al., Ann. Neurol. 29(4):435-8(1991)), and a delay in PCr recovery kinetics following exercise inskeletal muscle (Matthews et al., Ann. Neurol. 29(4):435-8 (1991);Barbiroli et al., J. Neurol. 242(71:472-7 (1995); Fabrizi et al., J.Neurol. Sci. 137(1):20-7 (1996)). A low skeletal muscle PCr has alsobeen confirmed in patients with mitochondrial cytopathy by directbiochemical measurements.

Exercise testing is particularly helpful as on evaluation and screeningtool in mitochondrial myopathies. One of the hallmark characteristics ofmitochondrial myopathies is a reduction in maximal whole body oxygenconsumption (VO2max) (Taivassalo et al., Brain 126(Pt 2):413-23 (2003)).Given that VO2max is determined by cardiac output (Qc) and peripheraloxygen extraction (arterial-venous total oxygen content) difference,some mitochondrial cytopathies affect cardiac function where deliverycan be altered; however, most mitochondrial myopathies show acharacteristic deficit in peripheral oxygen extraction (A-V O2difference) and an enhanced oxygen delivery (hyperkinetic circulation)(Taivassalo et al., Brain 126(Pt 2):413-23 (2003)). This can bedemonstrated by a lack of exercise induced deoxygenation of venous bloodwith direct AV balance measurements (Taivassalo et al., Ann. Neurol.51(1):38-44 (2002)) and non-invasively by near infrared spectroscopy(Lynch et al., Muscle Nerve 25(5):664-73 (2002); van Beekvelt et al.,Ann. Neurol. 46(4):667-70 (1999)).

Several of these energy biomarkers are discussed in more detail asfollows. It should be emphasized that, while certain energy biomarkersare discussed and enumerated herein, the invention is not limited tomodulation, normalization or enhancement of only these enumerated energybiomarkers.

Lactic acid (lactate) levels: Mitochondrial dysfunction typicallyresults in abnormal levels of lactic acid, as pyruvate levels increaseand pyruvate is converted to lactate to maintain capacity forglycolysis. Mitochondrial dysfunction can also result in abnormal levelsof NADH+h⁺, NADPH+H⁺, NAD or NADP, as the reduced nicotinamide adeninedinucleotides are not efficiently processed by the respiratory chain.Lactate levels can be measured by taking samples of appropriate bodilyfluids such as whole blood, plasma, or cerebrospinal fluid. Usingmagnetic resonance, lactate levels can be measured in virtually anyvolume of the body desired, such as the brain.

Measurement of cerebral lactic acidosis using magnetic resonance inMELAS patients is described in Kaufmann et al., Neurology 62(8): 1297(2004). Values of the levels of lactic acid in the lateral ventricles ofthe brain are presented for two mutations resulting in MELAS, A3243G andA8344G. Whole blood, plasma, and cerebrospinal fluid lactate levels canbe measured by commercially available equipment such as the YSI2300 STATPlus Glucose & Lactate Analyzer (YSI Life Sciences, Ohio).

NAD, NADP, NADH and NADPH levels: Measurement of NAD, NADP, NADH(NADH+H⁺) or NADPH (NADPH+H⁺) can be measured by a variety offluorescent, enzymatic, or electrochemical techniques, e.g., theelectrochemical assay described in US 2005/0067303.

Oxygen consumption (vO₂ or VO2), carbon dioxide output (vCO₂ or VCO2),and respiratory quotient (VCO2/VO2): vO₂ is usually measured eitherwhile resting (resting vO₂) or at maximal exercise intensity (vO₂ max).Optimally, both values will be measured. However, for severely disabledpatients, measurement of vO₂ max may be impractical. Measurement of bothforms of vO₂ is readily accomplished using standard equipment from avariety of vendors, e.g. Korr Medical Technologies, Inc. (Salt LakeCity, Utah). VCO2 can also be readily measured, and the ratio of VCO2 toVO2 under the same conditions (VCO2/VO2, either resting or at maximalexercise intensity) provides the respiratory quotient (RQ).

Oxidized Cytochrome C, reduced Cytochrome C, and ratio of oxidizedCytochrome C to reduced Cytochrome C: Cytochrome C parameters, such asoxidized cytochrome C levels (Cyt C_(ox)), reduced cytochrome C levels(Cyt C_(red)), and the ratio of oxidized cytochrome C/reduced cytochromeC ratio (Cyt C_(ox))/(Cyt C_(red)), can be measured by in vivo nearinfrared spectroscopy. See, e.g., Rolfe, P., “In vivo near-infraredspectroscopy.” Annu. Rev. Biomed. Eng. 2:715-54 (2000) and Strangman etal., “Non-invasive neuroimaging using near-infrared light” Biol.Psychiatry 52:679-93 (2002).

Exercise tolerance/Exercise intolerance: Exercise intolerance is definedas “the reduced ability to perform activities that involve dynamicmovement of large skeletal muscles because of symptoms of dyspnea orfatigue” (Piña et al., Circulation 107:1210 (2003)). Exerciseintolerance is often accompanied by myoglobinuria, due to breakdown ofmuscle tissue and subsequent excretion of muscle myoglobin in the urine.Various measures of exercise intolerance can be used, such as time spentwalking or running on a treadmill before exhaustion, time spent on anexercise bicycle (stationary bicycle) before exhaustion, and the like.Treatment with the compounds or methods of the invention can result inabout a 10% or greater improvement in exercise tolerance (for example,about a 10% or greater increase in time to exhaustion, e.g. from 10minutes to 11 minutes), about a 20% or greater improvement in exercisetolerance, about a 30% or greater improvement in exercise tolerance,about a 40% or greater improvement in exercise tolerance, about a 50% orgreater improvement in exercise tolerance, about a 75% or greaterimprovement in exercise tolerance, or about a 100% or greaterimprovement in exercise tolerance. While exercise tolerance is not,strictly speaking, an energy biomarker, for the purposes of theinvention, modulation, normalization, or enhancement of energybiomarkers includes modulation, normalization, or enhancement ofexercise tolerance.

Similarly, tests for normal and abnormal values of pyruvic acid(pyruvate) levels, lactate/pyruvate ratio, ATP levels, anaerobicthreshold, reduced coenzyme Q (CoQ^(red)) levels, oxidized coenzyme Q(CoQ^(ox)) levels, total coenzyme Q (CoQ^(tot)) levels, oxidizedcytochrome C levels, reduced cytochrome C levels, oxidized cytochromeC/reduced cytochrome C ratio, acetoacetate levels. βhydroxy butyratelevels, acetoacetate/β-hydroxy butyrate ratio.8-hydroxy-2′-deoxyguanosine (8-OHdG) levels, and levels of reactiveoxygen species are known in the art and can be used to evaluate efficacyof the compounds and methods of the invention. (For the purposes of theinvention, modulation, normalization, or enhancement of energybiomarkers includes modulation, normalization, or enhancement ofanaerobic threshold.)

Table 1, following, illustrates the effect that various dysfunctions canhave on biochemistry and energy biomarkers. It also indicates thephysical effect (such as a disease symptom or other effect of thedysfunction) typically associated with a given dysfunction. It should benoted that any of the energy biomarkers listed in the table, in additionto energy biomarkers enumerated elsewhere, can also be modulated,enhanced, or normalized by the compounds and methods of the invention.RQ=respiratory quotient; BMR=basal metabolic rate; HR (CO)=heart rate(cardiac output); T=body temperature (preferably measured as coretemperature); AT=anaerobic threshold; pH=blood pH (venous and/orarterial).

TABLE 1 Site of Biochemical Measurable Energy Physical Dysfunction EventBiomaker Effect Respiratory ↑ NADH Δ lactate, Metabolic Chain Δlactate:pyruvate dyscrasia & ratio; and fatigue Δ acetoacetate:β-hydroxy butyrate ratio Respiratory ↓ H⁺ gradient Δ ATP Organ dependentChain dysfunction Respiratory ↓ Electron Δ VO_(2,) RQ, BMR, MetabolicChain flux ΔT, AT, pH dyscrasia & fatigue Mitochondria ↓ ATP, ↓ VO₂ ΔWork, ΔHR (CO) Exercise & cytosol intolerance Mitochondria ↓ ATP Δ PCrExercise & cytosol intolerance Respiratory ↓ Cyt C_(Ox/Red) Δ λ~700-900nM Exercise Chain (Near Infrared intolerance Spectroscopy) Intermediary↓ Catabolism Δ C¹⁴-Labeled Metabolic metabolism substrates dyscrasia &fatigue Respiratory ↓ Electron Δ Mixed Venous Metabolic Chain flux VO₂dyscrasia & fatigue Mitochondria ↑ Oxidative Δ Tocopherol & Uncertain &cytosol stress Tocotrienols, CoQ10, docosahexanoic acid Mitochondria ↑Oxidative Δ Glutathione_(red) Uncertain & cytosol stress MitochondriaNucleic acid Δ8-hydroxy 2-deoxy Uncertain & cytosol oxidation guanosineMitochondria Lipid oxidation Δ Isoprostane(s), Uncertain & cytosoleicasonoids Cell membranes Lipid oxidation Δ Ethane (breath) UncertainCell membranes Lipid oxidation Δ Malondialdehyde Uncertain

Treatment of a subject afflicted by a mitochondrial disease inaccordance with the methods of the invention may result in theinducement of a reduction or alleviation of symptoms in the subject,e.g., to halt the further progression of the disorder.

Partial or complete suppression of the mitochondrial disease can resultin a lessening of the severity of one or more of the symptoms that thesubject would otherwise experience, for example, partial suppression ofMELAS could result in reduction in the number of stroke-like or seizureepisodes suffered.

Any one or any combination of the energy biomarkers described hereinprovide conveniently measurable benchmarks by which to gauge theeffectiveness of treatment or suppressive therapy. Additionally, otherenergy biomarkers are known to those skilled in the art and can bemonitored to evaluate the efficacy of treatment or suppressive therapy.

Use of Compounds for Modulation of Energy Biomarkers

In addition to monitoring energy biomarkers to assess the status oftreatment or suppression of mitochondrial diseases, the compounds of theinvention can be used in subjects or patients to modulate one or moreenergy biomarkers. Modulation of energy biomarkers can be done tonormalize energy biomarkers in a subject, or to enhance energybiomarkers in a subject.

Normalization of one or more energy biomarkers is defined as eitherrestoring the level of one or more such energy biomarkers to normal ornear-normal levels in a subject whose levels of one or more energybiomarkers show pathological differences from normal levels (i.e.,levels in a healthy subject), or to change the levels of one or moreenergy biomarkers to alleviate pathological symptoms in a subject.Depending on the nature of the energy biomarker, such levels may showmeasured values either above or below a normal value. For example, apathological lactate level is typically higher than the lactate level ina normal (i.e., healthy) person, and a decrease in the level may bedesirable. A pathological ATP level is typically lower than the ATPlevel in a normal (i.e., healthy) person, and an increase in the levelof ATP may be desirable. Accordingly, normalization of energy biomarkerscan involve restoring the level of energy biomarkers to within about atleast two standard deviations of normal in a subject, more preferably towithin about at least one standard deviation of normal in a subject, towithin about at least one-half standard deviation of normal, or towithin about at least one-quarter standard deviation of normal.

Enhancement of the level of one or more energy biomarkers is defined aschanging the extant levels of one or more energy biomarkers in a subjectto a level which provides beneficial or desired effects for the subject.For example, a person undergoing strenuous effort or prolonged vigorousphysical activity, such as mountain climbing, could benefit fromincreased ATP levels or decreased lactate levels. As described above,normalization of energy biomarkers may not achieve the optimum state fora subject with a mitochondrial disease, and such subjects can alsobenefit from enhancement of energy biomarkers. Examples of subjects whocould benefit from enhanced levels of one or more energy biomarkersinclude, but are not limited to, subjects undergoing strenuous orprolonged physical activity, subjects with chronic energy problems, orsubjects with chronic respiratory problems. Such subjects include, butare not limited to, pregnant females, particularly pregnant females inlabor; neonates, particularly premature neonates; subjects exposed toextreme environments, such as hot environments (temperatures routinelyexceeding about 85-86 degrees Fahrenheit or about 30 degrees Celsius forabout 4 hours daily or more), cold environments (temperatures routinelybelow about 32 degrees Fahrenheit or about 0 degrees Celsius for about 4hours daily or more), or environments with lower-than-average oxygencontent, higher-than-average carbon dioxide content, orhigher-than-average levels of air pollution (airline travelers, flightattendants, subjects at elevated altitudes, subjects living in citieswith lower-than-average air quality, subjects working in enclosedenvironments where air quality is degraded); subjects with lung diseasesor lower-than average lung capacity, such as tubercular patients, lungcancer patients, emphysema patients, and cystic fibrosis patients;subjects recovering from surgery or illness; elderly subjects, includingelderly subjects experiencing decreased energy; subjects suffering fromchronic fatigue, including chronic fatigue syndrome; subjects undergoingacute trauma; subjects in shock; subjects requiring acute oxygenadministration; subjects requiring chronic oxygen administration; orother subjects with acute, chronic, or ongoing energy demands who canbenefit from enhancement of energy biomarkers.

Accordingly, when an increase in a level of one or more energybiomarkers is beneficial to a subject, enhancement of the one or moreenergy biomarkers can involve increasing the level of the respectiveenergy biomarker or energy biomarkers to about at least one-quarterstandard deviation above normal, about at least one-half standarddeviation above normal, about at least one standard deviation abovenormal, or about at least two standard deviations above normal.Alternatively, the level of the one or more energy biomarkers can beincreased by about at least 10% above the subject's level of therespective one or more energy biomarkers before enhancement, by about atleast 20% above the subject's level of the respective one or more energybiomarkers before enhancement, by about at least 30% above the subject'slevel of the respective one or more energy biomarkers beforeenhancement, by about at least 40% above the subject's level of therespective one or more energy biomarkers before enhancement, by about atleast 50% above the subject's level of the respective one or more energybiomarkers before enhancement, by about at least 75% above the subject'slevel of the respective one or more energy biomarkers beforeenhancement, or by about at least 100% above the subject's level of therespective one or more energy biomarkers before enhancement.

When a decrease in a level of one or more energy biomarkers is desiredto enhance one or more energy biomarkers, the level of the one or moreenergy biomarkers can be decreased by an amount of about at leastone-quarter standard deviation of normal in a subject, decreased byabout at least one-half standard deviation of normal in a subject,decreased by about at least one standard deviation of normal in asubject, or decreased by about at least two standard deviations ofnormal in a subject. Alternatively, the level of the one or more energybiomarkers can be decreased by about at least 10% below the subject'slevel of the respective one or more energy biomarkers beforeenhancement, by about at least 20% below the subject's level of therespective one or more energy biomarkers before enhancement, by about atleast 30% below the subject's level of the respective one or more energybiomarkers before enhancement, by about at least 40% below the subject'slevel of the respective one or more energy biomarkers beforeenhancement, by about at least 50% below the subject's level of therespective one or more energy biomarkers before enhancement, by about atleast 75% below the subject's level of the respective one or more energybiomarkers before enhancement, or by about at least 90% below thesubject's level of the respective one or more energy biomarkers beforeenhancement.

Use of Compounds in Research Applications, Experimental Systems, andAssays

The compounds of the invention can also be used in researchapplications. They can be used in vitro, in vivo, or ex vivo experimentsto modulate one or more energy biomarkers in an experimental system.Such experimental systems can be cell samples, tissue samples, cellcomponents or mixtures of cell components, partial organs, whole organs,or organisms. Any one or more of the compounds of formula I, Ia, Iaa,Ib, and Ibb, can be used in experimental systems or researchapplications. Such research applications can include, but are notlimited to, use as assay reagents, elucidation of biochemical pathways,or evaluation of the effects of other agents on the metabolic state ofthe experimental system in the presence/absence of one or more compoundsof the invention.

Additionally, the compounds of the invention can be used in biochemicaltests or assays. Such tests can include incubation of one or morecompounds of the invention with a tissue or cell sample from a subjectto evaluate a subject's potential response (or the response of aspecific subset of subjects) to administration of said one or morecompounds, or to determine which compound of the invention produces theoptimum effect in a specific subject or subset of subjects. One suchtest or assay would involve 1) obtaining a cell sample or tissue samplefrom a subject in which modulation of one or more energy biomarkers canbe assayed; 2) administering one or more compounds of the invention tothe cell sample or tissue sample; and 3) determining the amount ofmodulation of the one or more energy biomarkers after administration ofthe one or more compounds, compared to the status of the energybiomarker prior to administration of the one or more compounds. Anothersuch test or assay would involve 1) obtaining a cell sample or tissuesample from a subject in which modulation of one or more energybiomarkers can be assayed; 2) administering at least two compounds ofthe invention to the cell sample or tissue sample; 3) determining theamount of modulation of the one or more energy biomarkers afteradministration of the at least two compounds, compared to the status ofthe energy biomarker prior to administration of the at least compounds,and 4) selecting a compound for use in treatment, suppression, ormodulation based on the amount of modulation determined in step 3).

Pharmaceutical Formulations

The compounds described herein can be formulated as pharmaceuticalcompositions by formulation with additives such as pharmaceuticallyacceptable excipients, pharmaceutically acceptable carriers, andpharmaceutically acceptable vehicles. Suitable pharmaceuticallyacceptable excipients, carriers and vehicles include processing agentsand drug delivery modifiers and enhancers, such as, for example, calciumphosphate, magnesium stearate, talc, monosaccharides, disaccharides,starch, gelatin, cellulose, methyl cellulose, sodium carboxymethylcellulose, dextrose, hydroxypropyl-β-cyclodextrin,polyvinylpyrrolidinone, low melting waxes, ion exchange resins, and thelike, as well as combinations of any two or more thereof. Other suitablepharmaceutically acceptable excipients are described in “Remington'sPharmaceutical Sciences,” Mack Pub. Co., New Jersey (1991), and“Remington: The Science and Practice of Pharmacy,” Lippincott Williams &Wilkins, Philadelphia, 20th edition (2003) and 21st edition (2005),incorporated herein by reference.

A pharmaceutical composition can comprise a unit dose formulation, wherethe unit dose is a dose sufficient to have a therapeutic or suppressiveeffect or an amount effective to modulate, normalize, or enhance anenergy biomarker. The unit dose may be sufficient as a single dose tohave a therapeutic or suppressive effect or an amount effective tomodulate, normalize, or enhance an energy biomarker. Alternatively, theunit dose may be a dose administered periodically in a course oftreatment or suppression of a disorder, or to modulate, normalize, orenhance an energy biomarker.

Pharmaceutical compositions containing the compounds of the inventionmay be in any form suitable for the intended method of administration,including, for example, a solution, a suspension, or an emulsion. Liquidcarriers are typically used in preparing solutions, suspensions, andemulsions. Liquid carriers contemplated for use in the practice of thepresent invention include, for example, water, saline, pharmaceuticallyacceptable organic solvent(s), pharmaceutically acceptable oils or fats,and the like, as well as mixtures of two or more thereof. The liquidcarrier may contain other suitable pharmaceutically acceptable additivessuch as solubilizers, emulsifiers, nutrients, buffers, preservatives,suspending agents, thickening agents, viscosity regulators, stabilizers,and the like. Suitable organic solvents include, for example, monohydricalcohols, such as ethanol, and polyhydric alcohols, such as glycols.Suitable oils include, for example, soybean oil, coconut oil, olive oil,safflower oil, cottonseed oil, and the like. For parenteraladministration, the carrier can also be an oily ester such as ethyloleate, isopropyl myristate, and the like. Compositions of the presentinvention may also be in the form of microparticles, microcapsules,liposomal encapsulates, and the like, as well as combinations of any twoor more thereof.

Time-release or controlled release delivery systems may be used, such asa diffusion controlled matrix system or an erodible system, as describedfor example in: Lee, “Diffusion-Controlled Matrix Systems”, pp. 155-108and Ron and Langer, “Erodible Systems”, pp. 199-224, in “Treatise onControlled Drug Delivery”, A. Kydonieus Ed., Marcel Dekker, Inc., NewYork 1992. The matrix may be, for example, a biodegradable material thatcan degrade spontaneously in situ and in vivo for, example, byhydrolysis or enzymatic cleavage, e.g., by proteases. The deliverysystem may be, for example, a naturally occurring or synthetic polymeror copolymer, for example in the form of a hydrogel. Exemplary polymerswith cleavable linkages include polyesters, polyorthoesters,polyanhydrides, polysaccharides, poly(phosphoesters), polyamides,polyurethanes, poly(imidocarbonates) and poly(phosphazenes).

The compounds of the invention may be administered enterally, orally,parenterally, sublingually, by inhalation (e.g. as mists or sprays),rectally, or topically in dosage unit formulations containingconventional nontoxic pharmaceutically acceptable carriers, adjuvants,and vehicles as desired. For example, suitable modes of administrationinclude oral, subcutaneous, transdermal, transmucosal, iontophoretic,intravenous, intraarterial, intramuscular, intraperitoneal, intranasal(e.g. via nasal mucosa), subdural, rectal, gastrointestinal, and thelike, and directly to a specific or affected organ or tissue. Fordelivery to the central nervous system, spinal and epiduraladministration, or administration to cerebral ventricles, can be used.Topical administration may also involve the use of transdermaladministration such as transdermal patches or iontophoresis devices. Theterm parenteral as used herein includes subcutaneous injections,intravenous, intramuscular, intrasternal injection, or infusiontechniques. The compounds are mixed with pharmaceutically acceptablecarriers, adjuvants, and vehicles appropriate for the desired route ofadministration. Oral administration is a preferred route ofadministration, and formulations suitable for oral administration arepreferred formulations. The compounds described for use herein can beadministered in solid form, in liquid form, in aerosol form, or in theform of tablets, pills, powder mixtures, capsules, granules,injectables, creams, solutions, suppositories, enemas, colonicirrigations, emulsions, dispersions, food premixes, and in othersuitable forms. The compounds can also be administered in liposomeformulations. The compounds can also be administered as prodrugs, wherethe prodrug undergoes transformation in the treated subject to a formwhich is therapeutically effective. Additional methods of administrationare known in the art.

Injectable preparations, for example, sterile injectable aqueous oroleaginous suspensions, may be formulated according to the known artusing suitable dispersing or wetting agents and suspending agents. Thesterile injectable preparation may also be a sterile injectable solutionor suspension in a nontoxic parenterally acceptable diluent or solvent,for example, as a solution in propylene glycol. Among the acceptablevehicles and solvents that may be employed are water, Ringer's solution,and isotonic sodium chloride solution. In addition, sterile, fixed oilsare conventionally employed as a solvent or suspending medium. For thispurpose any bland fixed oil may be employed including synthetic mono- ordiglycerides. In addition, fatty acids such as oleic acid find use inthe preparation of injectables.

Solid dosage forms for oral administration may include capsules,tablets, pills, powders, and granules. In such solid dosage forms, theactive compound may be admixed with at least one inert diluent such assucrose, lactose, or starch. Such dosage forms may also compriseadditional substances other than inert diluents, e.g., lubricatingagents such as magnesium stearate. In the case of capsules, tablets, andpills, the dosage forms may also comprise buffering agents. Tablets andpills can additionally be prepared with enteric coatings.

Liquid dosage forms for oral administration may include pharmaceuticallyacceptable emulsions, solutions, suspensions, syrups, and elixirscontaining inert diluents commonly used in the art, such as water. Suchcompositions may also comprise adjuvants, such as wetting agents,emulsifylng and suspending agents, cyclodextrins, and sweetening,flavoring, and perfuming agents.

The compounds of the present invention can also be administered in theform of liposomes. As is known in the art, liposomes are generallyderived from phospholipids or other lipid substances. Liposomes areformed by mono- or multilamellar hydrated liquid crystals that aredispersed in an aqueous medium. Any non-toxic, physiologicallyacceptable and metabolizable lipid capable of forming liposomes can beused. The present compositions in liposome form can contain, in additionto a compound of the present invention, stabilizers, preservatives,excipients, and the like. The preferred lipids are the phospholipids andphosphatidyl cholines (lecithins), both natural and synthetic. Methodsto form liposomes are known in the art. See, for example, Prescott, Ed.,Methods in Cell Biology, Volume XIV, Academic Press, New York, N.W., p.33 et seq (1976).

The invention also provides articles of manufacture and kits containingmaterials useful for treating or suppressing mitochondrial diseases. Theinvention also provides kits comprising any one or more of the compoundsof formulas I, Ia, Iaa, Ib, Ibb. In some embodiments, the kit of theinvention comprises the container described above.

In other aspects, the kits may be used for any of the methods describedherein, including, for example, to treat an individual with amitochondrial disorder, or to suppress a mitochondrial disorder in anindividual.

The amount of active ingredient that may be combined with the carriermaterials to produce a single dosage form will vary depending upon thehost to which the active ingredient is administered and the particularmode of administration. It will be understood, however, that thespecific dose level for any particular patient will depend upon avariety of factors including the activity of the specific compoundemployed, the age, body weight, body area, body mass index (BMI),general health, sex, diet, time of administration, route ofadministration, rate of excretion, drug combination, and the type,progression, and severity of the particular disease undergoing therapy.The pharmaceutical unit dosage chosen is usually fabricated andadministered to provide a defined final concentration of drug in theblood, tissues, organs, or other targeted region of the body. Thetherapeutically effective amount or effective amount for a givensituation can be readily determined by routine experimentation and iswithin the skill and judgment of the ordinary clinician.

Examples of dosages which can be used are an effective amount within thedosage range of about 0.1 mg/kg to about 300 mg/kg body weight, orwithin about 1.0 mg/kg to about 100 mg/kg body weight, or within about1.0 mg/kg to about 50 mg/kg body weight, or within about 1.0 mg/kg toabout 30 mg/kg body weight, or within about 1.0 mg/kg to about 10 mg/kgbody weight, or within about 10 mg/kg to about 100 mg/kg body weight, orwithin about 50 mg/kg to about 150 mg/kg body weight, or within about100 mg/kg to about 200 mg/kg body weight, or within about 150 mg/kg toabout 250 mg/kg body weight, or within about 200 mg/kg to about 300mg/kg body weight, or within about 250 mg/kg to about 300 mg/kg bodyweight. Compounds of the present invention may be administered in asingle daily dose, or the total daily dosage may be administered individed dosage of two, three or four times daily.

While the compounds of the invention can be administered as the soleactive pharmaceutical agent, they can also be used in combination withone or more other agents used in the treatment or suppression ofdisorders. Representative agents useful in combination with thecompounds of the invention for the treatment or suppression ofmitochondrial diseases include, but are not limited to, Coenzyme Q,vitamin E, idebenone, MitoQ, vitamins, and antioxidant compounds.

When additional active agents are used in combination with the compoundsof the present invention, the additional active agents may generally beemployed in therapeutic amounts as indicated in the Physicians' DeskReference (PDR) 53rd Edition (1999), or such therapeutically usefulamounts as would be known to one of ordinary skill in the art.

The compounds of the invention and the other therapeutically activeagents can be administered at the recommended maximum clinical dosage orat lower doses. Dosage levels of the active compounds in thecompositions of the invention may be varied so as to obtain a desiredtherapeutic response depending on the route of administration, severityof the disease and the response of the patient. When administered incombination with other therapeutic agents, the therapeutic agents can beformulated as separate compositions that are given at the same time ordifferent times, or the therapeutic agents can be given as a singlecomposition.

The invention will be further understood by the following nonlimitingexamples.

In general, the nomenclature used in this Application was generated withthe help of naming package within the ChemOffice®, version 11.0 suite ofprograms by CambridgeSoft Corp (Cambridge, Mass.).

Preparation of Compounds of the Invention

The compounds of this invention can be prepared from readily availablestarting materials using the following general methods and procedures.It will be appreciated that where typical or preferred processconditions (i.e., reaction temperatures, times, mole ratios ofreactants, solvents, pressures, etc.) are given, other processconditions can also be used unless otherwise stated. Optimum reactionconditions may vary with the particular reactants or solvent used, butsuch conditions can be determined by one skilled in the art by routineoptimization procedures.

Furthermore, the compounds of this invention will typically contain oneor more chiral centers. Accordingly, if desired, such compounds can beprepared or isolated as pure stereoisomers, i.e., as individualenantiomers or diastereomers, or as stereoisomer-enriched mixtures. Allsuch stereoisomers (and enriched mixtures) are included within the scopeof this invention, unless otherwise indicated. Pure stereoisomers (orenriched mixtures) may be prepared using, for example, optically activestarting materials or stereoselective reagents well-known in the art.Alternatively, racemic mixtures of such compounds can be separatedusing, for example, chiral column chromatography, chiral resolvingagents and the like.

Protocol A

Synthesis of 6-hydroxy-2,6,7,8-tetramethylchroman-2-carboxamides

6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (1 equiv.) wasdissolved to 0.2 M THF and the stirred pale yellow solution treated withcarbonyldiimidazole (CDI) (1.1 equiv.). The reaction was let stir forone hour and a solution of amine (1.1 equiv 0.2 M in THF) was added overone hour and the reaction stirred overnight. The solution wasconcentrated, dissolved to 0.04 M in CH₂Cl₂ and washed sequentially withhalf-volumes of 0.5 M HCl, 1.0 M NaHCO₃, saturated NaCl, the organiclayer dried over Na₂SO₄ and concentrated. Flash chromatography yieldedthe desired 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamidederivative.

Protocol B

Oxidation of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamides

A solution of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide (1.0equiv.) in 3 mL AcCN (0.28 M) and a drop of water was cooled to 0° C. Asolution of ceric ammonium nitrate (CAN) (2.2 equiv) in water (0.5 M)cooled to 0° C. was added dropwise over 2-3 minutes. The solution wasthen immediately treated with 10 mL EtOAc and the layers separated. Theorganic layer was washed 3×5 mL H₂O and the combined aqueous phases backextracted with 3×5 mL EtOAc. The combined organics were washed with 10mL saturated NaCl and dried over Na₂SO₄. Flash chromatography yieldedthe desired2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamidederivative.

Example 1N-tert-Butyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 355mg CDI (2.20 mmol) and 160 mg t-butylamine (2.20 mmol) produced 125.1 mgof N-tert-butyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide as awhite crystalline solid.

¹H NMR (400 MHz, CDCl₃) δ 6.40 (br s, 1H), 4.51 (s, 1H), 2.60 (m, 2H),2.26 (m, 1H), 2.19 (s, 3H), 2.16 (S, 3H), 2.10 (s, 3H), 1.88 (m, 1H),1.47 (s, 3H), 1.26 (m, 9H).

Oxidation as described in protocol B, using 95 mg (0.311 mmol) ofN-tert-butyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide and 358mg CAN (0.653 mmol) yielded 92.2 mgN-tert-butyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 6.61 (br s, 1H), 3.45 (s,1H), 2.55 (m, 1H), 2.39 (m, 1H), 2.04-1.91 (m, 10H), 1.56 (m, 1H), 1.37(m, 12H).

Example 22-Hydroxy-N,N,2-trimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 504 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.01 mmol), 361mg CDI (2.23 mmol) and 1.1 mL of a 2.0 M solution of NN-dimethylamine inTHF (2.2 mmol) produced 412 mg of6-hydroxy-N,N,2,5,7,8-hexamethylchroman-2-carboxamide as amorphouspowder.

¹H NMR (400 MHz, CDCl₃) δ 4.31 (s, 1H), 3.26 (s, 3H), 2.85 (S, 3H),2.80-2.41 (m, 3H), 2.16 (s, 6H), 2.08 (s, 3H), 1.70-1.60 (m, 4H).

Oxidation as described in protocol B, using 138.6 mg (0.50 mmol) of6-hydroxy-N,N,2,5,7,8-hexamethylchroman-2-carboxamide and 560 mg CAN(1.02 mmol) yielded 139.9 mg of2-hydroxy-N,N,2-trimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 5.07 (s, 1H), 2.23 (br s, 3H), 3.07 (br s,3H), 2.51 (m, 1H), 2.33 (m, 1H), 2.02 (m, 3H), 1.99-1.94 (m, 7H), 1.69(m, 1H), 1.47 (s, 3H).

Example 3N-Benzyl-2-hydroxy-2-methyl-4(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-hexamethylchroman-2-carboxylic acid (2.0 mmol) 362 mgCDI (2.23 mmol) and 235 mg benzylamine (2.20 mmol) produced 507 mg ofN-benzyl-6-hydroxy-2,5,7,8-hexamethylchroman-2-carboxamide as a brownoil.

¹H NMR (400 MHz, CDCl₃) δ 7.22 (m, 3H), 7.00 (m, 2H), 6.76 (br t, 1H),4.81 (s, 1H), 4.50 (m, 1H), 4.35 (m, 1H), 2.62 (m, 2H), 2.45 (m, 1H),2.16 (s, 3H), 2.11 (S, 6H), 1.92 (m, 1H), 1.58 (s, 3H).

Oxidation as described in protocol B, using 130 mg (0.383 mmol) ofN-benzyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide and 441 mgCAN (0.805 mmol) yielded 119.7 mg ofN-benzyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow foam.

¹H NMR (400 MHz, CDCl₃) δ 7.26 (m, 6H), 4.42 (m, 2H), 3.57 (s, 1H), 2.56(m, 1H), 2.36 (m, 1H), 2.04-1.93 (m, 10H), 1.59 (m, 1H), 1.42 (s, 3H).

Example 4N-Ethyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg,6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 356mg CDI (2.20 mmol) and 1.1 mL of a 2.0 solution of ethylamine inmethanol (2.2 mmol) produced 334 mg of asN-ethyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide as a whitesolid.

¹H NMR (400 MHz, CDCl₃) δ 6.44 (br s, 1H), 4.40 (s, 1H), 3.24 (m, 2H),2.57 (m, 2H), 2.31 (m, 1H), 2.18 (s, 6H), 2.10 (s, 3H), 1.89 (m, 1H),1.49 (s, 3H), 1.07 (t, 3H).

Oxidation as described in protocol B, using 100 mg (0.360 mmol) ofN-ethyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide and 415 mgCAN (0.757 mmol) yielded 96.2 mg ofN-ethyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 6.87 (br s, 1H), 3.67 (s, 1H), 3.29 (m, 2H),2.56 (m, 1H), 2.38 (m, 1H), 2.10-1.97 (m, 10H), 1.59 (m, 1H), 1.39 (s,3H), 1.15 (t, 3H).

Example 52-Hydroxy-2-methyl-N-propyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 502.3 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.01 mmol), 358mg CDI (2.21 mmol) and 130 mg propylamine (2.20 mmol) produced 371 mg of6-hydroxy-2,5,7,8-tetramethyl-N-propylchroman-2-carboxamide as an offwhite syrup.

¹H NMR (400 MHz, CDCl₃) δ 6.50 (br s, 1H), 4.85 (br s, 1H), 3.18 (q,2H), 2.62 (m, 2H), 2.37 (m, 1H), 2.18 (s, 6H), 2.09 (s, 3H), 1.91 (m,1H), 1.50 (s, 3H), 1.42 (m, 2H), 0.80 (t, 3H).

Oxidation as described in protocol B, using 90.6 mg (0.311 mmol) of6-hydroxy-2,5,7,8-tetramethyl-N-propylchroman-2-carboxamide and 374.9 mgCAN (0.684 mmol) yielded2-hydroxy-2-methyl-N-propyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow powder.

¹H NMR (400 MHz, CDCl₃) δ 6.89 (br t, 1H), 3.61 (s, 1H), 2.21 (q, 2H),2.56 (m, 1H), 2.36 (m, 1H), 2.02 (m, 10H), 1.56 (m, 3H), 1.40 (m, 3H),0.92 (t, 3H).

Example 6N-(Cyclopropylmethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 502 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.01 mmol), 356mg CDI (2.20 mmol) and 158 mg cyclopropanemethylamine (2.22 mmolproduced 445 mg ofN-(cyclopropylmethyl)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamideas a clear colorless oil.

¹H NMR (400 MHz, CDCl₃) δ 6.53 (br s, 1H), 4.39 (s, 1H), 3.05 (m, 2H),2.57 (m, 2H), 2.31 (m, 2H), 2.17 (s, 6H), 2.08 (s, 3H), 1.90 (m, 1H),1.50 (m, 3H), 0.86 (m, 1H), 0.40 (m, 2H), 0.070 (m, 2H).

Oxidation as described in protocol B, using 76.7 mg (0.253 mmol) ofN-(cyclopropylmethyl)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamideand 435 mg CAN (0.794 mmol) yielded 71.4 mg ofN-(cyclopropylmethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow powder.

¹H NMR (400 MHz, CDCl₃) δ 6.93 (br t, 1H), 3.46 (s, 1H), 3.13 (t, 2H),2.58 (m, 1H), 2.42 (m, 1H), 2.05-1.84 (m, 10H), 1.60 (m, 1H), 1.42 (s,3H), 0.97 (m, 1H), 0.51 (m, 2H), 0.22 (m, 2H).

Example 72-Hydroxy-N-isopentyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 492 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (1.97 mmol), 370mg CDI (2.28 mmol) and 1.92 mg 3-methylbutamine (2.20 mmol) produced 375mg of 6-hydroxy-N-isopentyl-2,5,7,8-tetramethylchroman-2-carboxamide aswhite crystals.

Oxidation as described in protocol B, using 101 mg (0.316 mmol) of6-hydroxy-N-isopentyl-2,5,7,8-tetramethylchroman-2-carboxamide and 380mg CAN (0.694 mmol) yielded 101.2 mg of2-hydroxy-N-isopentyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 6.85 (br t, 1H), 3.65 (s, 1H), 3.65 (q, 2H),2.55 (m, 1H), 2.35 (m, 1H), 2.02-1.95 (m, 10H), 1.59 (m, 2H), 1.43-1.37(m, 5H), 0.89 (d, 6H).

Example 82-Hydroxy-2-methyl-N-phenethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 356mg CDL (2.20 mmol) and 266 mg phenethylamine (2.2 mmol) produced 440 mgof 6-hydroxy-2,5,7,8-tetramethyl-N-phenethylchroman-2-carboxamide as aclear pale brown oil.

¹H NMR (400 MHz, CDCl₃) δ 7.21 (m, 3H), 7.05 (m, 2H), 6.46 (bt t, 1H),4.29 (s, 1H), 3.52 (m, 2H), 2.78-2.57 (m, 3H), 2.48 (m, 1H), 2.33 (dt,1H), 2.16 (s, 3H), 2.09 (s, 3H), 1.98 (s, 3H), 1.82 (m, 1H), 1.47 (s,3H).

Oxidation as described in protocol B, using 102 mg (0.287 mmol) of6-hydroxy-2,5,7,8-tetramethyl-N-phenethylchroman-2-carboxamide and 355mg CAN (0.647 mmol) yielded 95.8 mg of2-hydroxy-2-methyl-N-phenethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 72.9 (m, 2H), 7.20 (m, 3H), 6.88 (br t, 1H),3.54 (m, 2H), 3.32 (s, 1H), 2.84 (t, 2H), 2.48 (m, 1H), 2.29 (m, 1H),2.02-1.94 (m, 10H), 1.54 (m, 1H), 1.36 (s, 3H).

Example 92-Hydroxy-N-(3-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 357mg CDI (2.20 mmol) and 165 mg 3-aminopropanol (2.2 mmol) produced 297 mgof6-hydroxy-N-(3-hydroxypropyl)-2,5,7,8-tetramethylchroman-2-carboxamideas an amorphous white solid.

¹H NMR (400 MHz, CDCl₃) δ 6.78 (br t, 1H), 4.88 (br s, 1H), 3.50-3.31(m, 5H), 2.66-2.49 (m, 2H), 2.33 (m, 1H), 2.17 (s, 6H), 2.09 (s, 3H),1.88 (m, 1H), 1.66-1.51 (m, 5H).

Oxidation as described in protocol B, using 56.7 mg (0.184 mmol) of6-hydroxy-N-(3-hydroxypropyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 222 mg CAN (0.406 mmol) yielded 49.7 mg of2-hydroxy-N-(3-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 7.19 (br t, 1H), 3.65 (q, 2H), 3.58 (br s,1H), 3.43 (m, 2H), 2.56 (m, 1H), 2.41 (m, 1H), 2.05-1.99 (m, 10H), 1.73(quintet, 2H), 1.61 (m, 1H), 1.42 (s, 3H).

Example 10N-Cyclopropyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 357mg CDI (2.00 mmol) and 126 mg cyclopropylamine (2.2 mmol) produced 227mg of N-cyclopropyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamideas a pale brown oil.

¹H NMR (400 MHz, CDCl₃) δ 6.50 (br s, 1H), 4.32 (br s, 1H), 2.68-2.58(m, 3H), 2.32 (m, 1H), 2.17 (s, 3H), 2.14 (s, 3H), 2.09 (s, 3H), 1.87(m, 1H), 1.48 (s, 3H), 0.75 (m, 2H), 0.38 (m, 2H).

Oxidation as described in protocol B, using 100 mg (0.346 mmol) ofN-cyclopropyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide and 417mg CAN (0.762 mmol) yielded 40 mg ofN-cyclopropyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 6.86 (br s, 1H), 3.45 (s, 1H), 2.74 (m, 1H),2.54 (m, 1H), 2.38 (m, 1H), 2.02-1.98 (m, 9H), 1.77 (d, 1H), 1.58 (m,1H), 1.39 (s, 3H), 0.79 (q, 2H), 0.53 (m, 2H).

Example 112-Hydroxy-N-isobutyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 510 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.04 mmol), 357mg CDI (2.20 mmol) and 161 mg isobutylamine (2.2 mmol) produced 467 mgof 6-hydroxy-N-isobutyl-2,5,7,8-tetramethylchroman-2-carboxamide as anoff-white solid.

¹H NMR (400 MHz, CDCl₃) δ 6.49 (br s, 1H), 4.29 (s, 1H), 3.09 (m, 1H),3.00 (m, 1H), 2.59 (m, 2H), 2.36 (dt, 1H), 2.10 (s, 6H), 2.09 (s, 3H),1.88 (m, 1H), 1.65 (m, 1H), 1.52 (s, 3H), 0.76 (dd, 6H).

Oxidation as described in protocol B, using 84 mg (0.278 mmol) of6-hydroxy-N-isobutyl-2,5,7,8-tetramethylchroman-2-carboxamide and 335 mgCAN (0.612 mmol) yielded 78 mg of2-hydroxy-N-isobutyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow-orange oil.

¹H NMR (400 MHz, CDCl₃) δ 6.94 (t, 1H), 3.55 (s, 1H), 3.09 (m, 2H), 2.58(m, 1H), 2.89 (m, 1H), 2.07-1.94 (m, 10H), 1.79 (m, 1H), 1.58 (m, 1H),1.41 (s, 3H), 0.88 (d, 6H).

Example 122-(3-Hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-(3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.0 mmol), 370mg CDI (2.28 mmol) and 222 mg 4-hydroxypiperidine (2.20 mmol) produced222 mg of a6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)(4-hydroxypiperidin-1-yl)methanoneas a white foam.

¹H NMR (400 MHz, CDCl₃) δ 4.56-4.31 (br d, 1H), 4.27 (br s, 1H), 4.08(br s, 1H), 3.85 (m, 1H), 3.56-3.46 (br m, 1H), 3.08 (br s, 1H), 3.77(m, 1H), 2.57 (n, 2H), 2.15 (s, 6H), 2.08 (m, 3H), 1.82 (br s, 2H), 1.69(m, 1H), 1.58 (br s, 6H).

Oxidation as described in protocol B, using 100 (0.302 mmol) of(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)(4-hydroxypiperidin-1-yl)methanoneand 364 mg CAN (0.664 mmol) yielded 95 mg of a yellow syrup.

¹H NMR (400 MHz, CDCl₃) δ 4.00 (m, 4H), 3.45 (m, 3H), 2.53-2.42 (m, 1H),2.05-1.92 (m, 10H), 1.71 (m, 1H), 1.56 (m, 3H), 1.49 (s, 3H).

Example 13N-ethyl-2-hydroxy-N,2-dimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 499 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 360mg CDI (2.22 mmol) and 130 mg N-methyl ethylamine (2.2 mmol) producedN-ethyl-6-hydroxy-N,2,5,7,8-pentamethylchroman-2-carboxamide as a clearoil.

¹H NMR (400 MHz, CDCl₃) δ 4.30 (br s, 1H), 3.82 (B, m, 2H), 3.44 (A, m,1H), 3.20 (A, s, 3H), 3.08 (A, m, 1H), 2.82 (B, s, 3H), 2.75 (m, 1H),2.66-2.52 (m, 2H), 2.16 (s, 6H), 2.08 (s, 3H), 1.70-1.58 (m, 4H), 1.03(A+B, dt, 3H), two rotomers in 60:40 mixture, A and B.

Oxidation as described in protocol B, using 78 mg (0.268 mmol) ofN-ethyl-6-hydroxy-N,2,5,7,8-pentamethylchroman-2-carboxamide and 323 mgCAN (0.590 mmol) yielded 76 mg ofN-ethyl-2-hydroxy-N,2-dimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 5.12 (br s, 1H), 3.61 (br s, 1H), 3.40 (br s,1H), 3.21 (s, 3H), 2.98 (br s, 1H), 2.51 (td, 1H), 2.35 (br s, 1H), 2.02(s, 3H), 1.97 (s, 6H), 1.67 (td, 1H), 1.46 (s, 3H), 1.80 (br m, 3H).

Example 142-(3-Hydroxy-3-methyl-4-(4-methylpiperazin-1-yl)-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione

Following the amide coupling procedure described in protocol A, 502 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.01 mmol), 354mg CDI (2.18 mmol) and 220 mg N-methylpiprazine (2.2 mmol) produced 557mg of6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)(4-methylpiperazin-1-yl)methanoneas a clear oil.

¹H NMR (400 MHz, CDCl₃) δ 4.02 (br s, 2H), 3.56 (br d, 2H), 2.78 (m,1H), 2.55 (m, 2H), 2.35 (br s, 4H), 2.24 (s, 3H), 2.16 (s, 3H), 2.13 (s,3H), 2.08 (s, 3H), 1.72 (m, 1H), 1.58 (s, 3H).

Oxidation as described in protocol B, using 122 mg (0.368 mmol) of(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)(4-methylpiperazin-1-yl)methanoneand 444 mg CAN (0.811 mmol) yielded2-(3-hydroxy-3-methyl-4-(4-methylpiperazin-1-yl)-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dioneas an orange oil, 67.9 mg.

¹H NMR (400 MHz, CDCl₃) δ 4.91 (br s, 1H), 3.77 (br m, 4H), 2.58-2.30(m, 8H), 2.04-1.76 (m, 10H), 1.71 (m, 1H), 1.48 (s, 3H).

Example 152-(4-(4-Benzylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione

Following the amide coupling procedure described in protocol A, 506 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.02 mmol), 365mg CDI (2.25 mmol) and 386 mg 1-benzylpiperazine (2.2 mmol) yielded 568mg of(4-benzylpiperazin-1-yl)(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)methanoneas a white powder.

¹H NMR (400 MHz, CDCl₃) δ 7.30 (m, 5H), 5.18 (br s, 1H), 4.06 (br m,2H), 3.66 (br s, 1H), 3.47 (dd, 2H), 2.78 (m, 1H), 2.58 (m, 2H), 2.39(m, 5H), 2.18 (s, 3H), 2.14 (s, 3H), 2.08 (s, 3H), 1.74 (m, 1H), 1.60(s, 3H).

Oxidation as described in protocol B, using 98 mg (0.242 mmol) of(4-benzylpiperazin-1-yl)(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)methanoneand 291 mg CAN (0.531 mmol) yielded 76 mg of2-(4-(4-benzylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dionas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 7.21 (m, 5H), 4.94 (s, 1H), 3.70 (br s, 2H),3.63 (br s, 2H), 3.98 (dd, 2H), 2.49-2.31 (m, 6H), 1.96 (s, 3H), 1.91(s, 6H), 1.84 (m, 1H), 1.61 (m, 1H), 1.30 (s, 3H). APCI-MS M⁺+H 425 m/z.

Example 162-Hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 498 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (1.99 mmol), 367mg CDI (2.26 mmol) and 1.4 mL of 7.0M NH₃ in MeOH (9.8 mmol) produced187 mg of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide as a whitesolid.

Oxidation as described in protocol B, using 186 mg (0.747 mmol) of6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide and 907 mg CAN (1.65mmol) yielded 157 mg of2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, d₄-MeOH) δ 2.71 (ddd, 1H), 2.39 (ddd, 1H), 2.01 (s,3H), 1.99 (s, 6H), 1.85 (ddd, 1H), 1.58 (m, 1H), 1.38 (s, 3H).

Example 172-Hydroxy-N-(4-hydroxybutyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 507 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.03 mmol), 356mg CDI (2.20 mmol) and 196 mg 4-aminobutanol (2.20 mmol) produced 488 mgof 6-hydroxy-N-(4-hydroxybutyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a white powder.

¹H NMR (400 MHz, d₄-MeOH) δ 7.22 (br t, 1H), 3.41 (t, 2H), 3.25 (m, 1H),3.12 (m, 1H), 2.61 (dt, 1H), 2.50 (m, 1H), 2.32 (dt, 1H), 2.16 (s, 3H),2.14 (s, 3H), 2.05 (s, 3H), 1.75 (m, 1H), 1.47 (s, 3H), 1.41 (m, 2H),1.28 (m, 2H).

Oxidation as described in protocol B, using 100 mg (0.311 mmol) of6-hydroxy-N-(4-hydroxybutyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 375 mg CAN (0.685 mmol) yielded2-hydroxy-N-(4-hydroxybutyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 7.12 (t, 1H), 3.97 (s, 1H), 3.67 (t, 2H), 3.29(q, 2H), 2.81 (br s, 1H), 3.56 (td, 1H), 2.34 (td, 1H), 2.02-1.92 (m,10H), 1.61 (m, 5H), 1.39 (s, 3H).

Example 182-Hydroxy-N-(5-hydroxypentyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 497 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (1.98 mmol), 370mg CDI (2.28 mmol) and 239 mg 5-aminopentanol (2.2 mmol) produced 468 mgof6-hydroxy-N-(5-hydroxypentyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a pale brown solid.

¹H NMR (400 MHz, d₄-MeOH) δ 7.16 (br t, 1H), 3.42 (t, 2H), 3.07 (m, 1H),2.60 (dt, 1H), 2.50 (m, 1H), 2.36 (m, 1H), 2.36 (m, 1H), 2.18 (s, 3H),2.16 (s, 3H), 2.06 (2, 3H), 1.78 (m, 1H), 1.49 (s, 3H), 1.37 (m, 4H),1.09 (m, 2H).

Oxidation as described in protocol B, using 96 mg (0.286 mmol) of6-hydroxy-N-(5-hydroxypentyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 345 mg CAN (0.629 mmol) yielded 92.8 mg of2-hydroxy-N-(5-hydroxypentyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 6.96 (t, 1H), 3.83 (br s, 1H), 3.65 (t, 2H),3.26 (q, 2H), 2.65 (td, 1H), 2.35 (m, 1H), 2.24 (br s, 1H), 2.02-1.93(m, 10H), 1.57 (m, 5H), 1.43 (m, 5H).

Example 192-Hydroxy-N-(1-hydroxypropan-2-yl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 365mg CDI (2.25 mmol) and 165 mg 2-amino-1-propanol (2.2 mmol) produced 488mg of6-hydroxy-N-(1-hydroxypropan-2-yl)-2,5,7,8-tetramethylchroman-2-carboxamideas a pale brown foam.

¹H NMR (400 MHz, CDCl₃) δ 7.31 (t, 0.4H), 7.21 (t, 0.6H), 3.97 (br s,1.5H), 3.83 (br s, 0.4), 3.56 (br s, 0.6H, 3.53-3.44 (m, 1H), 3.67 (brs, 0.4H), 3.16 (m, 1H), 2.58 (m, 1H), 2.36 (m, 1H), 2.03-1.90 (m, 10H),1.61 (m, 1H), 1.424 (s, 1.4H), 1.416 (s, 1.6H), 1.21 (d, 3H).

Oxidation as described in protocol B, using 102.2 mg (0.329 mmol) of6-hydroxy-N-(1-hydroxypropan-2-yl)-2,5,7,8-tetramethylchroman-2-carboxamideand 397 mg CAN (2.45 mmol) yielded 98.5 mg of2-hydroxy-N-(1-hydroxypropan-2-yl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow foam.

Example 202-Hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (5.00 g 19.98mmol) in 150 mL THF was treated with 3.65 g CDI (22.5 mmol) and theexothermic reaction let stir for 1 h at room temperature. Ethanolamine(1.35 g, 22.10 mmol) in 50 mL THF was added over 1 h and the solutionstirred overnight. The reaction was concentrated, dissolved into 375 mLCH₂Cl₂ and washed with 250 mL 0.1 M HCl, 250 mL 0.5 M NaHCO₃, 2×100 mLsaturated NaCl and dried over Na₂SO₄. The acidic aqueous phase wasextracted 3×100 mL CH₂Cl₂ and washed with 50 mL saturated NaCl and driedover Na₂SO₄. The combined organics were concentrated and purified byflash chromatography yielding 2.88 g of6-hydroxy-N-(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamide asan off white impure solid.

¹H NMR (400 MHz, CDCl₃) δ 6.88 (br s, 1H), 4.35 (t, 2H), 3.62 (m, 2H),3.39 (m, 2H), 2.60 (m, 2H), 2.50 (t, 2H), 2.34 (m, 1H), 2.27 (m, 1H),2.18 (s, 6H), 2.09 (s, 3H), 1.90 (m, 1H), 1.53 (s, 3H).

6-hydroxy-N-(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamide(2.38 g, 8.11 mmol) was dissolved into 150 mL AcCN, cooled to 0° C. andtreated with 9.75 g CAN (17.94 mmol) in 30 mL H₂O over 20 minutes. EtOAc(150 mL) and H₂O (20 mL) were then added, layers separated and theorganic phase washed 21×20 mL H₂O. The aqueous phase was back extracted4×50 mL EtOAc and the combined organics washed with saturated NaCl,dried over Na₂SO₄ and concentrated to a yellow powder. Flashchromatography yielded 1.68 g of2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, d₆-Ace) δ 7.55 (br s, 1H), 4.62 (s, 1H), 3.99 (t, 1H),3.62 (q, 2H), 3.34 (m, 2H), 2.69 (td, 1H), 2.36 (td, 1H), 1.98 (s, 9H),1.89 (m, 1H), 1.60 (m, 1H), 1.37 (s, 3H).

Example 212-Hydroxy-N-(2-methoxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 499 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 370mg CDI (2.28 mmol) and 165.2 mg 2-methoxyethylamine (2.20 mmol) produced6-hydroxy-N-(2-methoxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamide asa white crystalline solid.

Oxidation as described in protocol B, 101 mg (0.329 mmol) of2-methoxyethylamine (2.20 mmol) yielded6-hydroxy-N-(2-methoxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 396 mg CAN (0.724 mmol) yielding2-hydroxy-N-(2-methoxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow crystalline solid.

¹H NMR (400 MHz, CDCl₃) δ 7.14 (br s, 1H), 3.53 (s, 1H), 3.46 (m, 4H),3.35 (s, 3H), 2.58 (td, 1H), 2.37 (td, 1H), 2.05-1.94 (m, 10H), 1.60 (m,1H) 1.41 (s, 3H).

Example 22 Methyl2-(2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamido)acetate

Following the amide coupling procedure described in protocol A, 499 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), and361 mg CDI (2.23 mmol) were dissolved in THF. Glycine methyl esterhydrochloride (263.7 mg, 2.1 mmol) dissolved into 10 mL THF, 5 mLCH₂Cl₂, 100 μL Et₃N and 2.5 mL MeOH was added over 1 h. Workup asdescribed in protocol A, produced 471.3 mg of methyl2-hydroxy-(6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamido)acetate

¹H NMR (400 MHz, CDCl₃) δ 7.02 (br s, 1H), 4.10 (dd, 1H), 3.92 (dd, 1H),3.72 (s, 3H), 2.61 (m, 2H), 2.35 (m, 1H), 2.22 (s, 3H), 2.18 (s, 3H),2.09 (s, 3H), 1.91 (m, 1H), 1.53 (s, 3H).

Oxidation as described in protocol B, using 110 mg (0.344 mmol) ofmethyl2-hydroxy-(6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamido)acetateand 415 mg CAN (0.757 mmol) yielded 94.0 mg of methyl2-(2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6dioxocyclohexa-1,4-dienyl)butanamido)acetate as a yellow powder.

¹H NMR (400 MHz, CDCl₃) δ 7.41 (t, 1H), 4.05 (qd, 2H), 3.74 (s, 3H),3.62 (br s, 1H), 2.62 (td, 1H), 2.43 (m, 1H), 2.04 (m, 1H), 1.99 (s,6H), 1.97 (s, 3H), 1.61 (m, 1H), 1.43 (s, 3H).

Example 23N-(3-(1H-imidazol-1-yl)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

A solution of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid(500 mg, 2.00 mmol) in 10 mL THF was treated with 358 mg CDI and stirredfor 1.25 h at room temperature. To this clear yellow solution was addeda solution of 278 mg 1-(3-aminopropyl)imidazole in 10 mL THF over 1 h.The solution was stirred overnight at room temperature, concentrated toa pale brown oil, dissolved into 70 mL CH₂Cl₂, washed 1×50 mL saturatedNaCl, and dried over Na₂SO₄. The organic layers were concentrated andflashed chromatographed to yield 524 mg ofN-(3-(1H-imidazol-1-yl)propyl)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamideas a white crystalline solid.

¹H NMR (400 MHz, CDCl₃) δ 7.22 (s, 1H), 7.02 (s, 1H), 6.58 (s, 1H), 6.41(t, 1H), 3.71 (quint, 1H), 3.58 (quint, 1H), 3.37 (sextet, 1H), 3.02(sextet, 1H), 2.34 (dt, 1H), 2.54 (m, 1H), 2.44 (m, 1H), 2.20 (s, 6H),2.08 (s, 3H), 1.93 (m, 1H), 1.83 (m, 2H), 1.54 (s, 3H).

To a solution ofN-(3-(1H-imidazol-1-yl)propyl)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide(100.7 mg, 0.282 mmol) in 6 mL AcCN and 6 mL CH₂Cl₂, cooled to 0° C.,was added to a cooled solution of CAN (340 mg, 0.620 mmol) in 2 mL H₂O,dropwise over 5 minutes. The reaction was immediately treated with 5 mLEtOAc and washed 3×3 mL H₂O. The aqueous layer was basified with 6 mLsaturated NaHCO₃ solution and extracted 6×3 mL EtOAc. The combinedorganics were dried over Na₂SO₄ and concentrated to a yellow oil. Flashchromatography yielded 98.1 mg ofN-(3-(1H-imidazol-1-yl)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 7.56 (s, 1H), 7.05 (s, 1H), 6.97 (s, 1H), 4.02(t, 2H), 3.60 (br s, 1H), 3.29 (m, 2H), 2.60 (td, 1H), 2.37 (td, 1H),2.07-1.92 (m, 12H), 1.63 (m, 1H), 1.41 (s, 3H).

Example 24(R)-2-Hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 1.846 g6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (7.37 mmol),1.315 g CDI (8.11 mmol) and 991 mg ethanolamine (16.33 mmol) produced1.765 g of(R)-6-hydroxy-N-(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a waxy white solid.

¹H NMR (400 MHz, CDCl₃) δ 6.88 (br s, 1H), 3.63 (td, 2H), 3.39 (m, 2H),2.70-2.54 (m, 2H), 2.35 (dt, 1H), 2.18 (s, 6H), 2.10 (s, 3H), 1.90 (m,1H), 1.53 (s, 3H).

Oxidation as described in protocol B, using 1.49 g (5.11 mmol) ofprecursor(R)-6-hydroxy-N-(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 6.16 g CAN (11.2 mmol) yielded 1.46 g of(R)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a waxy yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 7.14 (br s, 1H), 3.78 (t, 2H), 3.48 (m, 2H),2.59 (m, 1H), 2.39 (m, 1H), 2.04-1.94 (m, 10H), 1.64 (m, 1H), 1.43 (s,3H).

Example 252-Hydroxy-N-(2-(2-hydroxyethoxy)ethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 501 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.0 mmol), 360mg CDI (2.23 mmol) and 231 mg 2-(2-aminoethoxy)ethanol (2.19 mmol)produced 557 mg of6-hydroxy-N-(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamide asan amorphous white solid.

¹H NMR (400 MHz, CDCl₃) δ 6.83 (br s, 1H), 3.36 (t, 2H), 3.53-3.36 (m,6H), 2.70 (m, 2H), 2.35 (dt, 1H), 2.18 (s, 6H), 2.09 (s, 3H), 1.88 (m,1H), 1.52 (s, 3H).

Oxidation as described in protocol B, using 98.1 mg (0.305 mmol) of6-hydroxy-N-(2-(2-hydroxyethoxy)ethyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 368 mg CAN (0.671 mmol) yielded2-hydroxy-N-(2(2-hydroxyethoxy)ethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 7.26 (t, 1H), 3.82 (br s, 1H), 3.74 (m, 2H),3.60 (m, 4H), 3.50 (m, 2H), 2.90 (br s, 1H), 2.57 (td, 1H), 2.38 (m,1H), 2.03-1.93 (m, 10H), 1.61 (m, 1H), 1.41 (s, 3H).

Example 262-Hydroxy-2-methyl-N-(2-(pryidin-2-yl)ethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 499 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (1.99 mmol), 3.70mg CDI (2.28 mmol) and 324 mg 2-picolylamine (3.0 mmol), produced 579 mgof6-hydroxy-2,5,7,8-tetramethyl-N-(pryidin-2-ylmethyl)chroman-2-carboxamideas a white solid.

¹H NMR (400 MHz, CDCl₃) δ 8.48 (d, 1H), 7.68 (br s, 1H), 7.58 (td, 1H),7.15 (m, 1H), 7.02 (d, 1H), 4.53 (m, 2H), 4.32 (s, 1H), 2.63 (m, 2H),2.39 (dt, 1H), 2.25 (s, 3H), 2.17 (s, 3H), 2.09 (s, 3H), 1.93 (m, 1H),1.56 (s, 3H).

A solution of6-hydroxy-2,5,7,8-tetramethyl-N-(pyridin-2-ylmethyl)chroman-2-carboxamide(104 mg, 0.307 mmol) in 4 mL AcCN was chilled to 0° C. and CAN (370 mgin 2 mL H₂O) added followed by 8 mL EtOAc, 4 mL 1.0 M NaHCO₃ and 250 mgK₂CO₃. The emulsion was extracted 5×4 mL EtOAc and the combined organicswashed 2×4 mL saturated NaCl, dried over Na₂SO₄ and concentrated toyellow oil. Flash chromatography yielded2-hydroxy-2-methyl-N-(pyridin-2-ylmethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide.

¹H NMR (400 MHz, CDCl₃) δ 8.51 (d, 1H), 8.02 (t, 1H), 7.65 (td, 1H),7.29 (d, 1H), 7.18 (dd, 1H), 4.55 (m, 2H), 4.39 (br s, 1H), 2.63 (m,1H), 2.34 (m, 1H), 1.99 (m, 1H), 1.96 (s, 3H), 1.93 (s, 6H), 1.66 (m,1H), 1.46 (s, 3H).

Example 272-Hydroxy-2-methyl-N-(2-(pyridin-2-yl)ethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

A solution of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid(500 mg, 2.0 mmol) in 10 mL THF was treated with 356 mg CDI (2.2 mmol).After 1 h, 366 mg 2-(2-methylaminoethyl)pyridine (3.0 mmol) in 10 mL THFwas added over 1 h and stirred overnight. The solution was concentrated,dissolved into 70 mL CH₂Cl₂, extracted once with 10 M NaHCO₃. Theaqueous phase was then back extracted 2×25 mL CH₂Cl₂ and the combinedorganics washed with 2×25 mL saturated NaCl and dried over Na₂SO₄. Thesolution was concentrated and purified by flash chromatography to give6-hydroxy-2,5,7,8-tetramethyl-N-(2-(pryidin-2-yl)ethyl)-chroman-2-carboxamide.

¹H NMR (400 MHz, CDCl₃) δ 8.43 (d, 1H), 7.52 (t, 1H), 7.12 (m, 2H), 6.98(d, 1H), 4.27 (s, 1H), 3.69 (q, 2H), 2.92 (m, 2H), 2.34 (dt, 1H), 2.52(m, 1H), 2.32 (m, 1H), 2.15 (s, 3H), 2.08 (s, 3H), 2.06 (s, 3H), 1.84(m, 1H), 1.46 (s, 3H).

6-Hydroxy-2,5,7,8-tetramethyl-N-(2-(pyridin-2-yl)ethyl)-chroman-2-carboxamide(97.7 mg, 0.276 mmol) was dissolved in 3 mL AcCN and 2 mL CH₂Cl₂ andcooled to 0° C. prior to treatment with 332.5 mg CAN (0.606 mmol) in 2mL H₂O. The reaction was quenched by the addition of 5 mL EtOAc and 4 mL1.0 M NaHCO₃ followed by extraction of the aqueous layer 3×5 mL EtOAc.the combined organics were back extracted 3×3 mL saturated NaCl, driedover Na₂SO₄ and concentrated. Flash chromatography yielded 85.8 mg of2-hydroxy-2-methyl-N-(2-(pyridin-2-yl)ethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 8.53 (d, 1H), 7.65 (t, 1H), 7.48 (br t, 1H),7.21 (m, 2H), 3.71 (q, 2H), 3.04 (t, 2H), 2.52 (m, 1H), 2.34 (m, 1H),2.00-1.89 (m, 10H), 2.58 (m, 1H), 1.37 (s, 3H).

Example 28(S)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 5.06 g6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (20.2 mmol), 3.68g CDI (22.7 mmol) and 2.44 g ethanolamine (39.52 mmol) produced 4.576 gof(S)-6-hydroxy-N-(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a white powder.

¹H NMR (400 MHz, CDCl₃) δ 6.88 (s, 1H), 3.64 (t, 2H), 3.39 (m, 2H), 2.62(m, 2H), 2.35 (dt, 1H), 2.18 (s, 6H), 2.10 (s, 3H), 1.90 (m, 1H), 1.53(s, 3H).

Oxidation as described in protocol B, using 3.50 g (11.93 mmol) of(S)-6-hydroxy-N-(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 13.73 g CAN (25.06 mmol) yielded 3.341 g of(S)-2-hydroxy-N-(2-hydroxethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 7.24 (t, 1H), 3.75 (t, 2H), 3.47 (m, 2H), 3.29(s, 2H), 2.58 (td, 1H), 2.35 (td, 1H), 2.00-1.94 (m, 10H), 1.61 (td,1H), 1.42 (s, 3H).

Example 292-Hydroxy-2-methyl-N-(3-(2-oxopyrrolidin-1-yl)-propyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 499 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.00 mmol), 357mg CDI (2.2 mmol) and 569 mg 1-(2-aminopropyl)pyrrolidin-2-one (4.0mmol) yielded 598 mg of6-hydroxy-2,5,7,8-tetramethyl-N-(3-(2-oxopyrrolidin-1-yl)propyl)chroman-2-carboxamideas a white powder.

¹H NMR (400 MHz, CDCl₃) δ 7.02 (t, 1H), 3.31 (m, 2H), 3.24 (m, 1H), 3.11(m, 2H), 2.59 (m, 2H), 2.37 (m, 3H), 2.24 (s, 3H), 2.17 (s, 3H), 2.08(s, 3H), 2.01 (m, 2H), 1.87 (m, 1H), 1.61 (m, 4H), 1.51 (s, 3H).

Oxidation as described in protocol B, using 113.2 mg (0.302 mmol) of6-hydroxy-2,5,7,8-tetramethyl-N-(3-(2-oxopyrrolidin-1-yl)propyl)chroman-2-carboxamideand 364.6 mg CAN (0.665 mmol) yielded 118 mg of2-hydroxy-2-methyl-N-(3-(2-oxopyrrolidin-1-yl)propyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 7.52 (br t, 1H), 3.41 (quintet, 4H), 3.26 (m,2H), 2.58 (td, 1H), 2.42 (m, 3H), 2.09-1.88 (m, 12H), 1.75 (m, 2H), 1.66(m, 1H), 1.44 (s, 3H).

Example 302-Hydroxy-N-(2-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 4.98 g6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (19.9 mmol), 3.99g CDI (24.6 mmol) and 3.01 g 3-amino-2-propanol (39.9 mmol), yielded5.15 g of6-hydroxy-N-(2-hydroxypropyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a white powder.

¹H NMR (400 MHz, CDCl₃) δ 6.83 (br s, 1H), 3.8 (m, 1H), 3.39 (m, 1H),3.11 (m, 1H), 2.62 (m, 2H), 2.38 (dt, 1H), 2.19 (s, 6H), 2.09 (s, 3H),1.88 (m, 1H), 1.53 (s, 3H), 1.07 (dd, 3H).

Oxidation as described in protocol B, using 505 mg (1.64 mmol) of6-hydroxy-N-(2-hydroxypropyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 1.99 mg CAN (3.62 mmol) yielded 496 mg of2-hydroxy-N-(1-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 7.21 (t, 0.5H), 7.07 (t, 0.5H), 3.98 (m, 1H),3.52 (m, 1H), 3.15 (m, 1H), 2.61 (m, 1H), 2.42 (m, 1H), 2.04-1.91 (m,10H), 1.63 (m, 1H), 1.42 (s, 1H), 1.24 (m, 3H).

Example 312-Hydroxy-N-(6-hydroxyhexyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.0 mmol), 356mg CDI (2.2 mmol) and 468 mg 6-amino-1-hexanol (4.0 mmol) yielded 161 mgof 6-hydroxy-N-(6-hydroxyhexyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a white solid.

¹H NMR (400 MHz, CDCl₃) δ 6.35 (t, 1H), 3.56 (t, 2H), 3.53 (sextet, 1H),3.05 (sextet, 1H), 2.58 (m, 2H), 2.42 (dt, 1H), 2.19 (s, 6H), 2.09 (s,3H), 1.83 (m, 1H), 1.53 (s, 3H), 1.53-1.29 (m, 5H), 1.20 (m, 2H), 0.99(m, 2H).

Oxidation as described in protocol B, using 64.2 mg (0.183 mmol) of6-hydroxy-N-(6-hydroxyhexyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 230 mg CAN (0.419 mmol) yielded 40 mg of2-hydroxy-N-(6-hydroxyhexyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 6.86 (t, 1H), 3.64 (t, 2H), 3.28 (q, 2H), 2.54(m, 1H), 2.39 (m, 1H), 2.04-1.99 (m, 10H), 1.55 (m, 7H), 1.38 (m, 5H).

Example 322-Hydroxy-N-(6-hydroxyhexyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 496 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (1.98 mmol), 376mg CDI (2.32 mmol) and 404 mg tetrahydrofuranylamine (4.0 mmol) produced408.0 mg of crude6-hydroxy-2,5,7,8-tetramethyl-N-((tetrahydrofuran-2-yl)methyl)chroman-2-carboxamide,which was oxidized following protocol B, with 335 mg CAN (0.612 mmol) toyield 74.7 mg of2-hydroxy-2-methyl-N-((tetrahydrofuran-2-yl)methyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 7.16 (m, 1H), 3.98 (m, 1H), 3.87 (m, 1H), 3.76(q, 1H), 3.56 (m, 1H), 3.3 (d, 1H), 3.20 (m, 1H), 2.59 (m, 1H), 2.40 (m,1H), 1.99 (m, 10H), 1.89 (q, 2H), 1.56 (m, 2H), 1.42 (s, 3H).

Example 332-Hydroxy-2-methyl-N-(3-morpholinopropyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

To a solution of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid(511 mg, 2.1 mmol) in 10 mL THF was added 356 mg CDI and stirred for 2h. 3-morpholino-propylamine (438 μl, 432 mg, 3.0 mmol) in 10 mL THF wasadded dropwise and stirred overnight. The reaction was concentrated,dissolved in 70 mL CH₂Cl₂, the organics washed once with 50 mL saturatedNaCl solution, dried over Na₂SO₄ and concentrated to brown oil. Flashchromatography yielded6-hydroxy-2,5,7,8-tetramethyl-N-(3-morpholinopropyl)chroman-2-carboxamideas a pale brown solid.

¹H NMR (400 MHz, CDCl₃) δ (br s, 1H), 4.38 (br s, 1H), 3.68 (br s, 4H),3.64 (m, 1H), 3.21 (m, 1H), 1.57 (m, 2H), 2.42-2.30 (m, 5H), 2.19 (s,3H), 2.17 (s, 3H), 2.09 (s, 3H), 1.84 (m, 1H), 1.61 (m, 4H), 1.52 (s,3H). LRMS, APCI (M⁺+1) 377.

To a solution of 100 mg (0.266 mmol) of6-hydroxy-2,5,7,8-tetramethyl-N-(3-morpholinopropyl)chroman-2-carboxamidein 5 mL AcCN and one drop of H₂O at 0° C., was added a solution of 320.3mg CAN (0.584 mmol) in 3 mL H₂O dropwise. The solution was treated with5 mL EtOAc and 5 mL saturated NaCl followed by ˜1 g of NaHCO₃ and 1 h ofvigorous stirring. The suspension was then extracted 3×5 mL 4:1isopropyl alcohol:isopropyl acetate solution and the combined organicsdried over Na₂SO₄, concentrated to a yellow oil and flashedchromatographed to yield 16 mg of2-hydroxy-2-methyl-N-(3-morpholinopropyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a dark yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 7.75 (t, 1H), 3.74 (m, 4H), 3.36 (m, 2H), 2.53(m, 4H), 2.40 (dt, 1H), 2.00 (s, 3H), 1.99 (s, 3H), 1.97 (s, 3), 1.95(m, 1H), 1.75 (m, 2H), 1.58 (m, 1H), 1.39 (s, 3H).

¹³C NMR (100 MHz, CDCl₃) δ 186.7, 187.4, 175.5, 143.3, 140.95, 140.91,140.2, 75.1, 66.5, 57.6, 53.6, 38.9, 38.6, 27.1, 25.0, 21.1, 12.4, 21.2,12.0.

Example 342-Hydroxy-N-methoxy-N,2-dimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

To a solution of 5.47 g6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (21.9 mmol) in170 mL THF was added 3.92 g CDI (24.2 mmol) and stirred for 1.25 h atroom temperature. To this was added a solution of 2.14 gN,O-dimethylhydroxylamine hydrochloride (21.97 mmol) and 8.2 gN,N-diisopropylethylamine in 50 mL CH₂Cl₂ dropwise over 1 h. Thereaction was stirred overnight, concentrated, 250 mL CH₂Cl₂ added andwashed sequentially with 100 mL 0.625 M HCl, 100 mL 1.0 M NaHCO₃ and 100mL saturated NaCl. The organics were dried over Na₂SO₄, concentrated andpurified by flash chromatography yielding 4.43 g of6-hydroxy-N-methoxy-N,2,5,7,8-pentamethylchroman-2-carboxamide as anoff-white crystalline solid.

¹H NMR (400 MHz, CDCl₃) δ 3.63 (s, 3H), 3.31 (s, 3H), 2.74-2.55 (m, 3H),2.18 (s, 3H), 2.16 (s, 3H), 2.08 (s, 3H), 1.73 (m, 1H), 1.59 (s, 3H).

Oxidation as described in protocol B, using 155 mg (0.528 mmol) of6-hydroxy-N-methoxy-N,2,5,7,8-pentamethylchroman-2-carboxamide and 637mg CAN (1.16 mmol) yielding 119.4 mg of2-hydroxy-N-methoxy-N,2-dimethyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 3.80 (s, 3H), 3.25 (s, 3H), 2.55 (dt, 1H),2.37 (dt, 1H), 2.03 (s, 3H), 1.99 (m, 7H), 1.68 (dt, 1H), 1.48 (s, 3H).

Example 352-Hydroxy-N,N-bis(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

To a solution of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid(500 mg, 2.00 mmol) in 10 mL THF was added 356 mg CDI (2.20 mmol). Afterstirring for 1.5 h., a solution of diethanolamine (231 mg, 2.2 mmol) in10 mL THF was added over 1 h and the reaction was stirred overnight. Thereaction was concentrated, dissolved into 70 mL CH₂Cl₂ and washedsequentially with 50 mL 0.62 M HCl, 50 mL 1.0 M NaHCO₃, 50 mL saturatedNaCl and dried over Na₂SO₄. The combined aqueous phases were extracted3×50 mL 3:1 isopropyl alcohol/isopropyl acetate which was dried andconcentrated to a brown oil. Flash chromatography yielded 63 mg of6-hydroxy-N,N-bis(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 4.35 (s, 1H), 4.11 (m, 1H), 3.91 (br m, 1H),3.81-3.65 (br m, 4H), 3.51 (br s, 2H), 2.71-2.57 (m, 4H), 2.16 (s, 6H),2.09 (s, 3H), 1.74 (m, 1H).

Oxidation as described in protocol B, using 68.4 mg (0.203 mmol) ofprecursor6-hydroxy-N,N-bis(2-hydroxyethyl)-2,5,7,8-tetramethylchroman-2-carboxamideand 244 mg CAN (0.446 mmol) yielding 18.4 mg of2-hydroxy-N,N-bis(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow oil (25.7%).

¹H NMR (400 MHz, CDCl₃) δ 4.0-3.5 (m, 8H), 2.56 (td, 1H), 2.42 (td, 1H),2.04 (s, 3H), 2.00 (s, 3H), 1.98 (s, 3H), 1.67 (m, 1H), 1.51 (s, 3H).

Example 36N-(4-Hydroxyphenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 500 mg6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (2.0 mmol), 356mg CDI (2.2 mmol) and 548 mg tyramine (4.0 mmol) produced 537.8 mg of6-hydroxy-N-(4-hydroxyphenethyl)-2,5,7,8-tetramethylchroman-2-carboxamideas a brown solid.

¹H NMR (400 MHz, d₆-DMSO) δ 9.16 (s, 1H), 7.51 (s, 1H), 7.17 (t, 1H),6.84 (d, 2H), 6.60 (d, 2H), 3.24 (q, 2H), 2.50 (m), 2.37 (m, 1H), 2.14(m, 1H), 2.10 (s, 3H), 2.01 (s, 3H), 1.99 (s, 3H), 1.69 (m, 1H), 1.32(s, 3H).

Oxidation as described in protocol B, using 100 mg6-hydroxy-N-(4-hydroxyphenethyl)-2,5,7,8-tetramethylchroman-2-carboxamide(0.271 mmol) and 325 mg CAN (0.595 mmol) yielded 15 mgN-(4-hydroxyphenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, d₄-MeOH) δ 7.75 (t, 1H), 7.00 (d, 2H), 6.63 (d, 2H),3.34 (m, 2H), 2.68 (t, 2H), 2.54 (m, 1H), 2.12 (m, 1H), 1.93 (s, 6H),1.90 (s, 3H). 1.78 (td, 1H), 1.48 (m, 1H), 1.28 (s, 3H).

Example 37N-(2-(Dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

Following the amide coupling procedure described in protocol A, 1.03 g6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (4.11 mmol),0.712 g CDI (4.39 mmol) and 704 mg N,N-dimethylethylenediamine (7.99mmol) produced 1 g ofN-(2-(dimethylamino)ethyl)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamideas a white crystalline solid.

¹H NMR (400 MHz, CDCl₃) δ 7.10 (br s, 1H), 4.28 (br s, 1H), 3.22 (m,2H), 2.60 (m, 2H), 2.33 (m, 2H), 2.23 (m, 6H), 2.09 (s, 9H), 1.89 (m,1H), 1.52 (s, 3H).

Oxidation as described in protocol B, using 150 mgN-(2-(dimethylamino)ethyl)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide(0.468 mmol) and 564 mg CAN (1.03 mmol) with exceptions as noted. Theaqueous phase was basified with NaHCO₃ (s), extracted with EtOAc and thecombined organics dried with Na₂SO₄, concentrated and flashed yielding131 mg (83%) ofN-(2-(dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamideas a yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 7.62 (t, 1H), 3.48 (q, 2H), 2.63 (m, 3H), 2.37(s, 6H), 2.30 (td, 1H), 1.96 (m, 10H), 1.57 (m, 1H), 1.41 (s, 3H).

Example 38N-(2-(Dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamidehydrochloride

A solution of 22.8 mg starting quinone in 2 mL MeOH was treated with 20μL of a 4.0 M HCl in dioxane solution. After five minutes, the yellowsolution was concentrated, redissolved in 0.2 mL MeOH and trituratedinto a large excess of Et₂O, concentrated after one hour and fresh Et₂Oadded. After 72 h the reaction was filtered and a yellow solidN-(2-(dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamidehydrochloride was collected (15.6 mg).

¹H NMR (400 MHz, CDCl₃) δ 9.09 (s, 1H), 5.02 (m, 1H), 4.85 (m, 1H), 4.59(t, J=5.6 Hz, 2H), 4.09 (s, 6H), 3.94 (td, 1H), 3.67 (td, 1H), 3.26 (s,3H), 3.23 ((s, 6H), 3.07 (td, 1H), 2.91 (td, 1H), 2.64 (s, 3H).

Example 39N-(2-(Dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamidemesylate

N-(2-(dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide(25 mg) was dissolved into 1 mL CH₂Cl₂ and 5.2 μL neat methanesulfonicacid added to the stirred yellow solution. The solution wasconcentrated, dissolved into CH₂Cl₂ and triturated from Et₂O giving 20mg ofN-(2-(dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamidemesylate as a yellow hydroscopic solid.

¹H NMR (400 MHz, CDCl₃) δ 7.9 (t, 1H), 3.87 (m, 1H), 3.56 (m, 1H), 3.32(m, 1H), 2.96 (s, 3H), 2.95 (s, 3H), 2.80 (s, 3H), 2.65 (td, 1H).

Example 40N-(3-(Dimethylamino)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide

N-(3-(dimethylamino)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamidewas prepared following the procedure of Example 37 but substitutingN,N-dimethylethylenediamine with N¹,N¹-dimethylpropane-1,3-diamine.

¹H NMR (400 MHz, CDCl₃) δ 7.2 (t, 1H), 3.36 (m, 1H), 3.2-3.3 (m, 3H),2.93 (s, 6H), 2.6 (m, 1H), 2.35 (m, 1H), 2.06 (m, 2H), 2.00 (s, 3H),1.98 (s, 3H), 1.95 (s, 3H), 1.82 (td, 1H), 1.62 (td, 1H), 1.43 (s, 3H).

Example 416,6′-(4,4′-(piperazine-1,4-diyl)bis(3-hydroxy-3-methyl-4-oxobutane-4,1-diyl))bis(2,3,5-trimethylcyclohexa-2,5-diene-1,4-dione)

A solution of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid(5.0 g, 20 mmol), pyridine (50 mL), and acetic anhydride (43 mL) werestirred for 5 h. Water was added and the mixture extracted into methylt-butyl ether (MTBE) (2×100 mL) and the combined organics washed withwater (2×200 mL), copper sulfate solution (2×200 mL), and finally brine(2×50 mL). The organic layer was collected, dried over sodium sulfateand de-colorized using activated charcoal and concentrated to a lightgreen foam. The crude material was redissolved in CH₂Cl₂ (50 mL) anddimethylformamide (2 drops) followed by oxalyl chloride (1.9 mL) addeddropwise. Immediate evolution of gas was observed. The mixture wasstirred open to the air for 2 h and the solvent removed to give2-(chlorocarbonyl)-2,5,7,8-tetramethylchroman-6-yl acetate (3.9 g, 13mmol), which was used without further purification.

2-(chlorocarbonyl)-2,5,7,8-tetramethylchroman-6-yl acetate (3.9 g, 13mmol) in CH₂Cl₂ (25 mL) was treated with di-isopropylethylamine (DIEA)(5.0 mL) followed by piperazine (0.48 g, 5.6 mmol). The reaction mixturewas auto-refluxed briefly upon piperazine addition. The reaction wasallowed to cool to ambient temperature and stirred for 16 h. The mixturewas then poured into MTBE (100 mL), the organic layer removed and washedwith saturated ammonium chloride solution (3×50 mL) then dried oversodium sulfate. Solvent was removed to provide2,2′-(piperazin-1,4-diylbis(oxomethylene))bis(2,5,7,8-tetramethyl-3,4,5,8-tetrahydro-2H-chromene-6,2-diyl)diacetate (3.7 g, 5.8 mmol) as an amorphous off-white solid, which wasused directly without further purification.

To a solution of2,2′-(piperazine-1,4-diylbis(oxomethylene))bis(2,5,7,8-tetramethyl-3,4,5,8-tetrahydro-2H-chromene-6,2-diyl)diacetate(2.36 g), THF (25 mL) and MeOH (10 mL) was added KOH (1.04 g as asolution in 10 mL MeOH). The reaction mixture was stirred at ambienttemperature for 16 h, after which time it was fully dissolved. To thestirred reaction mixture was then added CAN (9.16 g, 16.7 mmol) as asolution in water (50 mL). After 1 h, addition water was added (50 mL),causing the formation of a beige precipitate. The supernatant wasdecanted, and extracted with MTBE. Solvent was removed under vacuum togive a crude yellow product, which was purified by flash chromatography,eluting with EtOAc/hexane (30% to 100%) to provide6,6′-(4,4′-(piperazine-1,4-diyl)bis(3-hydroxy-3-methyl-4-oxobutane-4,1-diyl))bis(2,3,5-trimethylcyclohexa-2,5-diene-1,4-dione)as a hard amorphous yellow solid.

¹H NMR (400 MHz, CDCl₃) δ 5.50 (br s, 2H), 3.95 (br s, 4H), 2.50-3.28(br m, 6H), 2.50-2.40 (m, 4H), 2.02-1.90 (m, 18H), 1.75 (br m, 2H), 1.59(br m, 2H), 1.36 (s, 6H).

Example 422-(3-Hydroxy-3-methyl-4-oxo-4-(piperidin-1-yl)butyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione

6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (1.005 g, 4.00mmol) in 22 mL THF was treated with 722.8 mg CDI (4.4 mmol) and stirredfor 2 h at room temperature. The pale yellow solution was then treatedwith 450 μL (381 mg, 4.47 mmol) piperidine in 22 mL THF in 1-2 mLportions over 2 h. The reaction was stirred overnight at roomtemperature. The reaction was concentrated and the residue dissolved in100 mL CH₂Cl₂ and sequentially washed with 50 mL 0.25 M HCl, 50 mL 1.0 MNaHCO₃, 50 mL saturated NaCl and dried over Na₂SO₄. The organic phasewas concentrated. Flash chromatography yielded 992 mg of6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)(piperidin-1-yl)methanone asan off-white solid.

¹H NMR (400 MHz, CDCl₃) δ 4.42 (s, 1H), 3.95-3.83 (br m, 2H), 3.46 (brs, 2H), 2.77 (m, 1H), 2.63-2.52 (m, 2H), 2.16 (s, 3H), 2.15 (s, 3H),2.08 (S, 3H), 1.70 (m, 1H), 1.58-1.48 (m, 2H), 1.45-1.36 (br s, 2H).

A solution of 319 mg of6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)(piperidin-1-yl)methanone(1.02 mmol) in 5 mL MTBE which was treated with 1.077 g FeCl₃·6H₂O in 6mL H₂O. The reaction mixture rapidly turned black which faded to ayellow color over the course of the reaction. An additional 2 mL MTBEwas added and stirred vigorously for 3 h at room temp. The reaction wasquenched with 10 mL H₂O and 10 mL MTBE, the layers separated and theorganics washed with H₂O until colorless. The combined aqueous phaseswere extracted 2×10 mL MTBE and the combined organics washed withsaturated NaCl and dried over Na₂SO₄. Flash chromatography yielded 335mg of2-(3-hydroxy-3-methyl-4-oxo-4-(piperidin-1-yl)butyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dioneas a dark yellow oil.

¹H NMR (400 MHz, CDCl₃) δ 5.14 (s, 1H), 3.65-3.45 (br m, 4H), 2.48 (td,1H), 2.36 (dt, 1H), 1.97 (s, 3H), 1.94 (s, 6H), 1.88 (m, 1H), 1.68-1.57(m, 7H), 1.42 (s, 3H).

¹³C NMR (100 MHz, CDCl₃) δ 187.4, 187.1, 173.4, 143.4, 140.6, 140.5,140.1, 73.3, 38.9, 26.2, 25.9, 24.3, 21.3, 12.3, 12.2, 11.8.

Example 43 N-Hexyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide

6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (5.0 g, 19.99mmol) was dissolved in pyridine (18 mL) and Ac₂O added (10 mL) in oneportion. The exothermic reaction warmed to 40° C., was let cool to roomtemperature and stirred overnight. The crude reaction mixture wasquenched with 100 mL H₂O, stirred for 1 h followed by additional 100 mLH₂O and 1 h of stirring. A fine white precipitate of6-acetoxy-2,5,7,8-tetramethylchroman-2-carboxylic acid was formed andcollected by filtration (4.544 g).

Crude 6-acetoxy-2,5,7,8-tetramethylchroman-2-carboxylic acid wasdissolved in 30 mL CH₂Cl₂, 2 drops of DMF added followed by slowaddition of 1.5 mL oxalyl chloride. Gas evolved for 1 h and the solutionwas stirred overnight at room temperature. The reaction mixture wasconcentrated separated into five equal aliquots of2-(chlorocarbonyl)-2,5,7,8-tetramethylchroman-6-yl acetate.

To one of the above aliquots of crude2-(chlorocarbonyl)-2,5,7,8-tetramethylchroman-6-yl acetate in 10 mLCH₂Cl₂ was added 1.0 mL diisopropylethylamine followed by 315 mg1-hexylamine and overnight stirring. The reaction mixture was pouredinto 1.0 M citric acid and 50 mL EtOAc added. The organic layer wasseparated and purified by flash chromatography to give 781 mg of2-(hexylcarbamoyl)-2,5,7,8-tetramethylchroman-6-yl acetate, as a clearsyrup. MS (m/z): M⁺376.3

Crude 2-(hexylcarbamoyl)-2,5,7,8-tetramethylchroman-6-yl acetate (187mg, 0.25 mmol) in 1.25 mL MeOH was treated with 33.7 mg (0.625 mmol)NaOMe and let stir overnight. The stirred brown solution then wasdiluted with water (10 mL), neutralized with 2.5 M HCl (1.5 mL) and 10mL EtOAc added. The layers were separated and the organics dried overNa₂SO₄ and concentrated. Flash chromatography yielded 90 mg ofN-hexyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide.

¹H NMR (400 MHz, CDCl₃) δ 6.46 (t, 1H), 4.76 (s, 1H), 3.20 (m, 2H), 2.58(m, 3H), 2.18 (s, 6H), 2.09 (s, 3H), 1.88 (m, 1H), 1.51 (s, 3H), 1.38(m, 2H), 1.25-1.11 (m, 6H), 0.85 (t, 3H).

A solution of 75 mg ofN-hexyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide (0.225 mmol)in 2 mL MTBE was treated with 2.0 mL of 0.5 M FeCl₃·6H₂O and stirredvigorously for 24 h. The solution was treated with 5 mL H₂O and 50 mLMTBE, the layers were separated and the organics washed with 2×5 mL H₂O,2×5 mL saturated NaCl. The combined organics were dried over Na₂SO₄ andconcentrated. Flash chromatography yieldedN-hexyl-6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxamide as anorange-brown oil which was rechromatographed to yield 31 mg of a brightyellow oil.

¹H NMR (400 MHz, CDCl₃) δ 6.82 (t, 1H), 3.48 (s, 1H), 3.22 (q, 2H), 2.55(m, 1H), 2.36 (m, 1H), 2.04-1.96 (m, 10H), 1.61-1.46 (m, 3H), 1.38 (s,3H), 1.33-1.22 (m, 6H), 0.84 (t, 3H).

BIOLOGICAL EXAMPLES Example A Screening Compounds of the Invention inHuman Dermal Fibroblasts from Friedreich's Ataxia Patients

An initial screen was performed to identify compounds effective for theamelioration of redox disorders. Test samples, 4 reference compounds(idebenone, decylubiquinone, Trolox and α-tocopherol acetate), andsolvent controls were tested for their ability to rescue FRDAfibroblasts stressed by addition of L-buthionine (S,R)-sulfoximine(BSO), as described in Jauslin et al., Hum. Mol. Genet. 11(24):3055(2002), Jauslin et al., FASEB J. 17:1972-4 (2003), and InternationalPatent Application WO 2004/003565. Human dermal fibroblasts fromFriedreich's Ataxia patients have been shown to be hypersensitive toinhibition of the de novo synthesis of glutathione (GSH) withL-buthionine-(S,R)-sulfoximine (BSO), a specific inhibitor of GSHsynthetase (Jauslin et al., Hum. Mol. Genet. 11(24):3055 (2002)). Thisspecific BSO-mediated cell death can be prevented by administration ofantioxidants or molecules involved in the antioxidant pathway, such asα-tocopherol, selenium, or small molecule glutathione peroxidasemimetics. However, antioxidants differ in their potency, i.e. theconcentration at which they are able to rescue BSO-stressed FRDAfibroblasts.

MEM (a medium enriched in amino acids and vitamins, catalog no.1-31F24-1) and Medium 199 (M199, catalog no. 1-21F22-1) with Earle'sBalanced Salts, without phenol red, were purchased from Bioconcept.Fetal Calf Serum was obtained from PAA Laboratories. Basic fibroblastgrowth factor and epidermal growth factor were purchased from PeproTech.Penicillin-streptomycin-glutamine mix, L-buthionine (S,R)-sulfoximine,(+)-α-tocopherol acetate, decylubiquinone, and insulin from bovinepancreas were purchased from Sigma. Trolox(6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) was obtainedfrom Fluka. Idebenone was obtained from Chemo Iberica. Calcein AM waspurchased from Molecular Probes. Cell culture medium was made bycombining 125 ml M199 EBS, 50 ml Fetal Calf Serum, 100 U/ml penicillin,100 μg/ml streptomycin, 2 mM glutamine, 10 μg/ml insulin, 10 ng/ml EGF,and 10 ng/ml bFGF; MEM EBS was added to make the volume up to 500 ml. A10 mM BSO solution was prepared by dissolving 444 mg BSO in 200 ml ofmedium with subsequent filter-sterilization. During the course of theexperiments, this solution was stored at +4° C. The cells were obtainedfrom the Coriell Cell Repositories (Camden, NJ; repository numberGM04078) and grown in 10 cm tissue culture plates. Every third day, theywere split at a 1:3 ratio.

The test samples were supplied in 1.5 ml glass vials. The compounds werediluted with DMSO, ethanol or PBS to result in a 5 mM stock solution.Once dissolved, they were stored at −20° C. Reference antioxidants(idebenone, decylubiquinone, α-tocopherol acetate and trolox) weredissolved in DMSO.

Test samples were screened according to the following protocol: Aculture with FRDA fibroblasts was started from a 1 ml vial withapproximately 500,000 cells stored in liquid nitrogen. Cells werepropagated in 10 cm cell culture dishes by splitting every third day ina ratio of 1:3 until nine plates were available. Once confluent,fibroblasts were harvested. For 54 micro titer plates (96 well-MTP) atotal of 14.3 million cells (passage eight) were re-suspended in 480 mlmedium, corresponding to 100 μl medium with 3,000 cells/well. Theremaining cells were distributed in 10 cm cell culture plates (500,000cells/plate) for propagation. The plates were incubated overnight at 37°C. in a atmosphere with 95% humidity and 5% CO₂ to allow attachment ofthe cells to the culture plate.

MTP medium (243 μl) was added to a well of the microtiter plate. Thetest compounds were unfrozen, and 7.5 μl of a 5 mM stock solution wasdissolved in the well containing 243 μl medium, resulting in a 150 μMmaster solution. Serial dilutions from the master solution were made.The period between the single dilution steps was kept as short aspossible (generally less than 1 second).

Plates were kept overnight in the cell culture incubator. The next day,10 μl of a 10 mM BSO solution were added to the wells, resulting in a 1mM final BSO concentration. Forty-eight hours later, three plates wereexamined under a phase-contrast microscope to verify that the cells inthe 0% control (wells E1-H1) were clearly dead. The medium from allplates was discarded, and the remaining liquid was removed by gentlytapping the plate inversed onto a paper towel.

100 μl of PBS containing 1.2 μM Calcein AM were then added to each well.The plates were incubated for 50-70 minutes at room temperature. Afterthat time the PBS was discarded, the plate gently tapped on a papertowel and fluorescence (excitation/emission wavelengths of 485 nm and525 nm, respectively) was read on a Gemini fluorescence reader. Data wasimported into Microsoft Excel (EXCEL is a registered trademark ofMicrosoft Corporation for a spreadsheet program) and used to calculatethe EC₅₀ concentration for each compound.

The compounds were tested three times, i.e., the experiment wasperformed three times, the passage number of the cells increasing by onewith every repetition.

The solvents (DMSO, ethanol, PBS) neither had a detrimental effect onthe viability of non-BSO treated cells nor did they have a beneficialinfluence on BSO-treated fibroblasts even at the highest concentrationtested (1%). None of the compounds showed auto-fluorescence. Theviability of non-BSO treated fibroblasts was set as 100%, and theviability of the BSO- and compound-treated cells was calculated asrelative to this value.

The following table summarizes the EC₅₀ for the four control compounds.

EC₅₀ [μM] Compound Value 1 Value 2 Value 3 Average Stdev decylubiquinone0.05 0.035 0.03 0.038 0.010 alpha-tocopherol 0.4 0.15 0.35 0.30 0.13acetate Idebenone 1.5 1 1 1.2 0.3 Trolox 9 9 8 8.7 0.6

Certain compounds of the present invention such as:

-   2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(3-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione-   2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxybutyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(5-hydroxypentyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(1-hydroxypropan-2-yl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;    (R)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-(1H-imidazol-1-yl)-propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-(2-hydroxyethoxy)ethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-3-methyl-4-(4-methylpiperazin-1-yl)-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(4-(4-benzylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-(3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-hydroxy-2-methyl-N-(3-morpholinopropyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N,N-bis(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-(dimethylamino)ethyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxyphenethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   6,6′-(4,4′-(piperazine-1,4-diyl)bis(3-hydroxy-3-methyl-4-oxobutane-4,1-diyl))bis(2,3,5-trimethylcyclohexa-2,5-diene-1,4-dione);-   N-(3-(dimethylamino)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(3-hydroxy-3-methyl-4-oxo-4-(piperazin-1-yl)butyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (R)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (S)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (S)-2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   N-(2-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-methoxyphenyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;    exhibited protection against FRDA with an EC₅₀ of less than about    100 nM.

Example B Screening Compounds of the Invention in Fibroblasts fromHuntington's Patients

Compounds of the invention were tested using the screen as described inExample A, but substituting FRDA cells with Huntington's cells obtainedfrom the Coriell Cell Repositories (Camden, NJ; repository number GM04281). The compounds were tested for their ability to rescue humandermal fibroblasts from Huntington's patients from oxidative stress.

Certain compounds of the present invention such as:

-   2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(3-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxybutyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(5-hydroxypentyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(1-hydroxypropan-2-yl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (R)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-(1H-imidazol-1-yl)-propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-(2-hydroxyethoxy)ethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(3-(2-oxopyrrolidin-1-yl)propyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-3-methyl-4-(4-methylpiperazin-1-yl)-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(4-(4-benzylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-(3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-hydroxy-2-methyl-N-(3-morpholinopropyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N,N-bis(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-(dimethylamino)ethyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxyphenethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   6,6′-(4,4′-(piperazine-1,4-diyl)bis(3-hydroxy-3-methyl-4-oxobutane-4,1-diyl))bis(2,3,5-trimethylcyclohexa-2,5-diene-1,4-dione);-   N-(3-(dimethylamino)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (R)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (S)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   N-(4-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-methoxyphenyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;    exhibited protection against Hungtington's with an EC₅₀ of less than    about 100 nM.

Example C Screening Compounds of the Invention in Fibroblasts fromLeber's Hereditary Optic Neuropathy Patients

Compounds of the invention were screened as described in Example A, butsubstituting FRDA cells with Leber's Hereditary Optic Neuropathy (LHON)cells obtained from the Coriell Cell Repositories (Camden, NJ;repository number GM03858). The compounds were tested for their abilityto rescue human dermal fibroblasts from LHON patients from oxidativestress.

Certain compounds of the present invention such as:

-   2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(3-hydroxy-3-methyl-4-oxo-4-(piperidin-1-yl)butyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(4-(azepan-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   N-hexyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-hexyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(3-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-isopentyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxybutyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(5-hydroxypentyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(1-hydroxypropan-2-yl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-(2-hydroxyethoxy)ethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxypropyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(4-(4-benzylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-(3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   N-(2-(dimethylamino)ethyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxyphenethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   6,6′-(4,4′-(piperazine-1,4-diyl)bis(3-hydroxy-3-methyl-4-oxobutane-4,1-diyl))bis(2,3,5-trimethylcyclohexa-2,5-diene-1,4-dione);-   2-hydroxy-2-methyl-N-(pyridin-4-ylmethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(pyridin-3-ylmethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(3-(methylsulfonyl)propyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(4-(4-benzoylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (R)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (S)-2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (R)-2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (S)-2-(3-hydroxy-4-(4-hydroxypiperidin-1-yl)-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   N-(2-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(3-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorobenzyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;    exhibited protection against LHON with an EC₅₀ of less than about    100 nM

Example D Screening Compounds of the Invention in Fibroblasts fromParkinson's Disease Patients

Compounds of the invention were screened as described in Example A, butsubstituting FRDA cells with Parkinson's Disease (PD) cells obtainedfrom the Coriell Cell Repositories (Camden, NJ; repository numberAG20439). The compounds were tested for their ability to rescue humandermal fibroblasts from Parkinson's Disease patients from oxidativestress.

Certain compounds of the present invention such as:

-   2-hydroxy-N-isopropyl-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(5-hydroxypentyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (R)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (S)-2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (R)-(3-(1H-imidazol-1-yl)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(2-hydroxyethoxy)ethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(4-(4-benzylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   (N)-(2-(dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-N-(4-hydroxyphenethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   (N)-(3-(dimethylamino)propyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;    exhibited protection against PD with an EC₅₀ of less than about 100    nM

Example E Screening Compounds of the Invention in Fibroblasts from CoQ10Deficient Patients

Compounds of the invention were tested using a screen similar to the onedescribed in Example A, but substituting FRDA cells with cells obtainedfrom CoQ10 deficient patients harboring a CoQ2 mutation. The compoundswere tested for their ability to rescue human dermal fibroblasts fromCoQ10 deficient patients from oxidative stress.

-   2-hydroxy-N-(2-hydroxyethyl)-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-hexyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-(dimethylamino)ethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-hydroxy-2-methyl-N-(pyridin-3-ylmethyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   2-(4-(4-acetylpiperazin-1-yl)-3-hydroxy-3-methyl-4-oxobutyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   2-(3-hydroxy-3-methyl-4-oxo-4-(piperazin-1-yl)butyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;-   tert-butyl    4-(2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanoyl)piperazine-1-carboxylate;-   (S)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(2-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-fluorophenyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;-   N-(4-chlorophenethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;    exhibited protection against CoQ10 deficiency with an EC₅₀ of less    than about 100 nM.

Example F Screening Compounds of the Invention in Human DermalFibroblasts from Autistic Patients

A screen was performed to identify compounds effective for theamelioration of ASD. Test samples, and solvent controls were tested fortheir ability to rescue ASD fibroblasts stressed by addition ofL-buthionine-(S,R)-sulfoximine (BSO).

MEM (a medium enriched in amino acids and vitamins, catalog no. Gibco11965) and Fetal Calf Serum were obtained from Invitrogen. Basicfibroblast growth factor and epidermal growth factor were purchased fromPeproTecb. Penicillin-streptomycin-glutamine mix, L-buthionine(S,R)-sulfoximine, and insulin from bovine pancreas were purchased fromSigma. Calcein AM was purchased from Molecular Probes. Cell culturemedium (ATP) was made by combining 75 ml Fetal Calf Serum, 100 U/mlpenicillin, 100 μg/ml streptomycin, 2 mM glutamine, 10 ng/ml EGF, and 10ng/ml bFGF; MEM EBS was added to make the volume up to 500 ml. A 10 mMBSO solution was prepared by dissolving 444 mg BSO in 200 ml of mediumwith subsequent filter-sterilization. During the course of theexperiments, this solution was stored at +4° C. The cells obtained fromDr. J. M. Shoffner, Medical Neurogenetics, Atlanta, Ga. were grown in 10cm tissue culture plates. Every week, they were split at a 1:3 ratio.The samples were supplied in 1.5 ml glass vials. The compounds werediluted with DMSO, ethanol or PBS to result in a 5 mM stock solution.Once dissolved, they were stored at −20° C.

The samples were screened according to the following protocol: A culturewith ASD fibroblasts was started from a 1 ml vial with approximately500,000 cells stored in liquid nitrogen. Cells were propagated in 10 cmcell culture dishes by splitting every week in a ratio of 1:3 until nineplates were available. Once confluent, fibroblasts were harvested. For54 micro titer plates (96 well-MTP) a total of 14.3 million cells(passage eight) were re-suspended in 480 ml medium, corresponding to 100μl medium with 3,000 cells/well. The remaining cells were distributed in10 cm cell culture plates (500,000 cells/plate) for propagation. Theplates were incubated overnight at 37° C. in an atmosphere with 95%humidity and 5% CO₂ to allow attachment of the cells to the cultureplate.

MTP medium (243 μl) was added to a well of the microtiter plate. Thetest compounds were unfrozen, and 7.5 μl of a 5 mM stock solution wasdissolved in the well containing 243 μl medium, resulting in a 150 μMmaster solution. Serial dilutions from the master solution were made.The period between the single dilution steps was kept as short aspossible (generally less than 1 second).

Plates were kept overnight in the cell culture incubator. The next day.10 μl of a 10 mM BSO solution were added to the wells, resulting in a 1mM final BSO concentration. Forty-eight hours later, three plates wereexamined under a phase-contrast microscope to verify that the cells inthe 0% control (wells E1-H1) were clearly dead. The medium from allplates was discarded, and the remaining liquid was removed by gentlytapping the plate inversed onto a paper towel.

100 μl of PBS containing 1.2 μM Calcein AM were then added to each well.The plates were incubated for 50-70 minutes at room temperature. Afterthat time the PBS was discarded, the plate gently tapped on a papertowel and fluorescence (excitation/emission wavelengths of 485 nm and525 nm, respectively) was read on a Gemini fluorescence reader. Data wasimported into Microsoft Excel (EXCEL is a registered trademark ofMicrosoft Corporation for a spreadsheet program) and used to calculatethe EC₅₀ concentration for each compound.

The compounds were tested three times, i.e., the experiment wasperformed three times, the passage number of the cells increasing by onewith every repetition.

The solvents (DMSO, ethanol, PBS) neither had a detrimental effect onthe viability of non-BSO treated cells nor did they have a beneficialinfluence on BSO-treated fibroblasts even at the highest concentrationtested (1%). None of the compounds showed auto-fluorescence. Theviability of non-BSO treated fibroblasts was set as 100%, and theviability of the BSO- and compound-treated cells was calculated asrelative to this value.

Compounds of the present invention are considered to be active if theyexhibit protection against ASD with an EC₅₀ of less than 300 nM. Acompound of the invention was tested using the protocol above, andshowed 50 nM activity.

The disclosures of all publications, patents, patent applications andpublished patent applications referred to herein by an identifyingcitation are hereby incorporated herein by reference in their entirety.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, it is apparent to those skilled in the art that certainminor changes and modifications will be practiced. Therefore, thedescription and examples should not be construed as limiting the scopeof the invention.

What is claimed is:
 1. A method of treating a mitochondrial disorder,the method comprising contacting mitochondria in a cell of a subjectwith a therapeutically effective amount or effective amount of one ormore compounds selected from Formula I:

where R is selected from the group consisting of

where the * indicates the point of attachment of R to the remainder ofthe molecule; R¹, R², and R³ are independently selected from hydrogenand C₁-C₆-alkyl; R⁴ is C₁-C₆-alkyl; R⁵ is hydrogen; R⁶ is selected fromhydroxy, alkoxy, C₁-C₄₀-alkyl, C₂-C₄₀-alkenyl, C₂-C₄₀-alkynyl, and aryl;where the alkyl, alkenyl, alkynyl, and aryl groups are optionallysubstituted with —OR¹⁰, —S(O)₀₋₂R¹⁰, —CN, —F, —Cl, —Br, —I,—NR¹⁰R^(10′), oxo, C₃-C₆-cycloalkyl, aryl, aryl-C₁-C₆-alkyl, heteroaryl,heterocyclyl, —C(O)—R¹¹, —C(O)—C₀-C₆-alkyl-aryl, —C(O)—O—R¹¹,—C(O)—O—C₀-C₆-alkyl-aryl, —C(O)—NR¹¹R¹¹, —C(O)—NH—C₀-C₆-alkyl-aryl,—NH—C(O)—R¹¹, —NH—C(O)—C₀-C₆-alkyl-aryl; where the aryl, heteroaryl andheterocyclyl ring substituents may be further substituted withC₁-C₆-alkyl, C₁-C₆-haloalkyl, oxo, hydroxy, C₁-C₆-alkoxy,—C(O)—C₁-C₆-alkyl and —C(O)—O—C₁-C₆-alkyl; and where one of the carbonsof the alkyl, alkenyl, or alkynyl groups may be substituted with aheteroatom selected from —O—, —N— or —S—; or R⁵ and R⁶ together with theatom to which they are attached form a saturated or unsaturated 3-8membered ring, optionally incorporating 1, 2, or 3 additional N, O, or Satoms, optionally substituted with oxo, —OR¹⁰, —SR¹⁰, —CN, —F, —Cl, —Br,—I, —NR¹⁰R^(10′), C₁-C₆-alkyl, C₁-C₆-haloalkyl; hydroxy-C₁-C₆-alkyl,—C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl, —C(O)—OH, or—C(O)—O—C₁-C₆-alkyl; or R⁵ and R⁶ together with the nitrogen atom towhich they are attached form a N,N′-disubstituted piperazine where thenitrogen substitution at the 4-position is a group identical to thesubstitution at the 1-position forming a compound of formula Iaa or Ibb,where R¹, R², R³, and R⁴ are as defined above:

R¹⁰ and R^(10′) are independently selected from the group consisting ofhydrogen, C₁-C₆-alkyl, C₁-C₆-haloalkyl, aryl, aryl-C₁-C₆-alkyl,heteroaryl, heterocyclyl, —C(O)—H, —C(O)—C₁-C₆-alkyl, —C(O)-aryl and—C(O)—C₁-C₆-alkyl-aryl; R¹¹ and R^(11′) are selected from hydrogen andC₁-C₆-alkyl; and M and M′ are independently selected from hydrogen,—C(O)—R¹², —C(O)—C₁-C₆-alkenyl, —C(O)—C₁-C₆-alkynyl, —C(O)-aryl;—C(O)-heteroaryl, —C(O)O—R¹², —C(O)NR¹²R¹², —SO₂OR¹², —SO₂—C₁-C₆-alkyl,—SO₂-haloC₁-C₆-alkyl; —SO₂-aryl, —SO₂—NR¹²R¹², —P(O)(OR¹²)(OR¹²), andC-linked mono or di-peptide, where R¹² is hydrogen or C₁-C₆-alkyloptionally substituted with —OH, —NH₂, —NH(C₁-C₄alkyl), —N(C₁-C₄alkyl)₂,—C(O)—OH, —C(O)—O—C₁-C₄-alkyl or halogen; and a salt, a stereoisomer,and a mixture of stereoisomers thereof; wherein the mitochondrialdisorder is selected from the group consisting of Leber's HereditaryOptic Neuropathy (LHON); Kearns-Sayre Syndrome (KSS); Friedreich'sAtaxia (FA) Parkinson's disease, and Huntington's Disease.
 2. The methodof claim 1, where the one or more compounds are selected from compoundswhere R⁵ is hydrogen and R⁶ is C₁-C₆ alkyl; and a salt, a stereoisomer,and a mixture of stereoisomers thereof.
 3. The method of claim 1, wherethe one or more compounds of Formula I are selected from Formula Ia:

and a salt, a stereoisomer, and a mixture of stereoisomers thereof. 4.The method of claim 3, where the mitochondrial disorder is selected fromthe group consisting of Leber's Hereditary Optic Neuropathy (LHON);Leigh Disease; Friedreich's Ataxia (FA); encephalomyopathy; Parkinson'sdisease; amyotrophic lateral sclerosis (ALS); and Huntington's Disease.5. The method of claim 3, where the mitochondrial disease is selectedfrom group consisting of Leber's Hereditary Optic Neuropathy (LHON);Leigh Disease; and Friedreich's Ataxia (FA).
 6. The method of claim 1,where in the one or more compounds of Formula I are selected fromFormula Ib

R¹, R², and R³ are each methyl; R⁴ is methyl; and a salt, astereoisomer, and a mixture of stereoisomers.
 7. The method of claim 6,where the one or more compounds is selected from compounds where R⁵ ishydrogen and R⁶ is C₁-C₆ alkyl and a salt, a stereoisomer, and a mixtureof stereoisomers.
 8. The method of claim 3, where the one or morecompounds are selected from compounds where one of the carbons of theR⁶C₁-C₆-alkyl group is replaced with a heteroatom selected from thegroup consisting of —O—, —N—, and —S— and where the R⁶C₁-C₆-alkyl groupis cyclic or a combination of cyclic and linear or branched; and a salt,a stereoisomer, and a mixture of stereoisomers thereof.
 9. The method ofclaim 7, where the one or more compounds are selected from compoundswhere one of the carbons of the R⁶C₁-C₆-alkyl group is replaced with aheteroatom selected from the group consisting of —O—, —N—, and —S— andwhere the R⁶C₁-C₆-alkyl group is cyclic or a combination of cyclic andlinear or branched; and a salt, a stereoisomer, and a mixture ofstereoisomers thereof.
 10. The method of claim 1, where the one or morecompounds are selected fromN-(cyclopropylmethyl)-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;N-cyclopropyl-2-hydroxy-2-methyl-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;2-hydroxy-2-methyl-N-((tetrahydrofuran-2-yl)methyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;2-(3-hydroxy-3-methyl-4-oxo-4-(piperidin-1-yl)butyl)-3,5,6-trimethylcyclohexa-2,5-diene-1,4-dione;and2-hydroxy-2-methyl-N-(3-(2-oxopyrrolidin-1-yl)propyl)-4-(2,4,5-trimethyl-3,6-dioxocyclohexa-1,4-dienyl)butanamide;and a salt, a stereoisomer, and a mixture of stereoisomers thereof. 11.The method of claim 1, wherein mitochondria in the cell in the subjectare defective.
 12. The method of claim 11, wherein the contacting occursin a tissue in the subject.
 13. The method of claim 11, wherein thecontacting occurs in an organ in the subject.